Method and apparatus for transmitting power headroom information in a communication system

ABSTRACT

The present disclosure relates to a communication method and system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for internet of things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. In addition, a method of a terminal in a wireless communication system, includes: receiving system information including first uplink waveform information for an initial access; transmitting a radio resource control (RRC) connection request message based on the first uplink waveform information; receiving an RRC connection response message including second uplink waveform information for uplink data transmission; and transmitting data based on the second uplink waveform.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application is based on and claims priority under 35 U.S.C. § 119to Korean Patent Application No. 10-2017-0057013, filed on May 4, 2017,and to Korean Patent Application No. 10-2017-0076154, filed on Jun. 15,2017 in the Korean Intellectual Property Office, the disclosure of whichis incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Various embodiments of the present disclosure relate to a communicationsystem, and more particularly, to a method and apparatus fortransmitting and receiving power headroom information in a communicationsystem.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a “beyond 4G network” or a“post LTE system.” The 5G communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, an analog beam forming, large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like. In the 5G system, hybrid FSK and QAM Modulation (FQAM) andsliding window superposition coding (SWSC) as an advanced codingmodulation (ACM), and filter bank multi carrier (FBMC), non-orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA) as anadvanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the internetof things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The internet ofeverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology,”“wired/wireless communication and network infrastructure,” “serviceinterface technology,” and “Security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing information technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, machine type communication (MTC), andmachine-to-machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud radioaccess network (RAN) as the above-described Big Data processingtechnology may also be considered to be as an example of convergencebetween the 5G technology and the IoT technology.

Meanwhile, in the conventional LTE, the terminal transmits powerheadroom information to the base station on an uplink. At this time, apower headroom value means a difference between a maximum transmissionpower of the terminal and a transmission power actually used for anuplink transmission by the terminal. The base station may use a methodfor using power headroom information received from a terminal tooptimize system performance. For example, if the power headroominformation received from the terminal is a positive value, the basestation may determine that the corresponding terminal may increase theuplink transmission power to increase the amount of resources which maybe allocated to the corresponding terminal upon scheduling of thecorresponding terminal. On the contrary, if the power headroominformation received from the terminal is a negative value, the basestation may determine that the corresponding terminal may reduce theuplink transmission power to reduce the amount of resources which may beallocated to the corresponding terminal upon scheduling of thecorresponding terminal. With this operation, coverage of data (orcontrol information) transmitted on the uplink may be ensured and thepower consumption of the terminal may be reduced.

Since the operation of transmitting and receiving the power headroominformation of the base station and the terminal is required even in the5G communication system using the beamforming, it is necessary to designa method and apparatus for transmitting power headroom information in abeamforming system.

SUMMARY

Accordingly, embodiments of the present disclosure are directed to theprovision of a method and an apparatus for operating a terminal and abase station for reducing delay for a transmission of terminal powerheadroom information in a communication system.

Another object of the present disclosure is directed to provision of amethod and an apparatus for operating a terminal and a base station fortransmitting terminal power headroom information according to a changein beam in a beamforming system.

Objects of the present disclosure are not limited to the above-mentionedobjects. That is, other objects that are not mentioned may be obviouslyunderstood by those skilled in the art to which the present disclosurepertains from the following description.

Various embodiments of the present disclosure are directed to theprovision of a method of a terminal in a wireless communication system,including: receiving system information including first uplink waveforminformation for an initial access; transmitting a radio resource controlRRC connection request message based on the first uplink waveforminformation; receiving an RRC connection response message includingsecond uplink waveform information for uplink data transmission; andtransmitting data based on the second uplink waveform.

Various embodiments of the present disclosure are directed to theprovision of a method of a base station in a wireless communicationsystem, including: transmitting system information including firstuplink waveform information for an initial access; receiving a radioresource control RRC connection request message based on the firstuplink waveform information; transmitting an RRC connection responsemessage including second uplink waveform information for uplink datatransmission; and receiving data based on the second uplink waveform.

Various embodiments of the present disclosure are directed to theprovision of a terminal in a wireless communication system, including: atransceiver; and a controller configured to: receive system informationincluding first uplink waveform information for an initial access;transmit a radio resource control RRC connection request message basedon the first uplink waveform information; receive an RRC connectionresponse message including second uplink waveform information for uplinkdata transmission; and transmit data based on the second uplinkwaveform.

Various embodiments of the present disclosure are directed to theprovision of a base station in a wireless communication system,including: a transceiver; and a controller configured to: transmitsystem information including first uplink waveform information for aninitial access; receive a radio resource control RRC connection requestmessage based on the first uplink waveform information; transmit an RRCconnection response message including second uplink waveform informationfor uplink data transmission; and receive data based on the seconduplink waveform.

According to the embodiment of the present disclosure, the method fortransmitting power headroom information can previously perform theuplink (UL) resource allocation for the transmission of the powerheadroom information to reduce a delay of uplink transmission upon thetransmission of the cell level mobility or beam level mobility controlsignal in the communication system.

In addition, according to the embodiment of the present disclosure, itis possible to maximize the system performance and to reduce the powerconsumption of the terminal by transmitting the terminal power headroominformation according to the change in beam in the system using thebeamforming.

The effects that may be achieved by the embodiments of the presentdisclosure are not limited to the above-mentioned objects. That is,other effects that are not mentioned may be obviously understood bythose skilled in the art to which the present disclosure pertains fromthe following description.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout thispatent document, those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 schematically illustrates a structure of a (5G, NR) communicationsystem according to an embodiment of the present disclosure, and is anexample of a configuration of an MME, an S-GW, and a 5G base station(gNB).

FIG. 2 schematically illustrates the structure of the (5G, NR)communication system according to the embodiment of the presentdisclosure, and is an example of a configuration of CU, DU, and TRxP.

FIG. 3 illustrates an example of an operation of calculating andtransmitting power headroom information for an uplink power control.

FIG. 4 illustrates an example of a change in an uplink beam.

FIG. 5 illustrates an example of the change in the uplink beam.

FIG. 6 illustrates an example of an operation of setting the number ofPHs included in the PHR for a transmission of power headroominformation.

FIG. 7 illustrates an example of an operation of newly introducing a PHRtriggering event when a beam for the transmission of the power headroominformation is changed and reducing a delay when the corresponding PHRis transmitted (when an intra-TRxP beam is changed).

FIG. 8 illustrates an example of an operation of newly introducing a PHRtriggering event when a beam for the transmission of the power headroominformation is changed and reducing a delay when the corresponding PHRis transmitted (when an inter-TRxP beam is changed).

FIG. 9 illustrates an example of an operation of transmitting powerheadroom information when a beam switch operation is performed (anoperation of transmitting the existing beam switch message when a PHRevent is not triggered).

FIG. 10 illustrates an example of an operation of transmitting powerheadroom information when the beam switch operation is performed(operation of adding PH related information to the existing beam switchmessage and transmitting the same when the PHR event between theIntra-TRxPs is triggered).

FIG. 11 illustrates an example of an operation of transmitting powerheadroom information when the beam switch operation is performed(operation of adding PH related information to the existing beam switchmessage and transmitting the same when the PHR event between theinter-TRxPs is triggered in the terminal).

FIG. 12 illustrates an example of an operation of transmitting powerheadroom information when the beam switch operation is performed(operation of adding PH related information to the existing beam switchmessage and transmitting the same when the PHR event between theinter-TRxPs is triggered in the base station).

FIG. 13 illustrates an example of transmitting UL data through aplurality of uplink beam-pairs (when a plurality of beams of the basestation, which is an uplink reception beam, exists within the sameTRxP).

FIG. 14 illustrates an example of transmitting the UL data through theplurality of uplink beam-pairs (when the plurality of beams of the basestation, which is the uplink reception beam, separately exists withinanother TRxP).

FIG. 15 illustrates an example of transmitting the UL data when thebeam-pair of the downlink and the beam-pair of the uplink are different(when the beam of the base station which is the downlink transmissionbeam and the beam of the base station which is the uplink reception beamexist within the same TRxP).

FIG. 16 illustrates an example of transmitting the UL data when thebeam-pair of the downlink and the beam-pair of the uplink are different(when the beam of the base station which is the downlink transmissionbeam and the beam of the base station which is the uplink reception beamseparately exist within another TRxP).

FIG. 17 illustrates an example of an operation of performing an uplinkresource allocation by transmitting, by the terminal, information on SR,BSR, and PHR to the base station and receiving an UL grant from the basestation in the LTE for the uplink resource allocation, and an example ofa required time delay.

FIG. 18 illustrates an example of an operation of configuring a PHRTriggering event related to a beam width change for the transmission ofthe power headroom information considering beamforming.

FIG. 19 is illustrates an example of a MAC CE format for thetransmission of the power headroom information considering thebeamforming (example of applying PH per beam).

FIG. 20 is illustrates another example of the MAC CE format for thetransmission of the power headroom information considering thebeamforming (example of applying PH per TRxP).

FIG. 21A illustrates a method in which a base station determines anuplink waveform and transmits information on a dynamic uplink waveformchange to DCI transmitted on a PDCCH to a terminal according to anembodiment of the present disclosure.

FIG. 21B illustrates a method for transmitting information on a dynamicuplink waveform change to UCI transmitted on a PUCCH as a method inwhich a terminal feeds back an uplink waveform to a base station andtransmits an uplink waveform according to an embodiment of the presentdisclosure.

FIG. 22A illustrates a method in which a base station determines anuplink waveform and indicates the determined uplink waveform to aterminal by a downlink MAC CE according to an embodiment of the presentdisclosure.

FIG. 22B illustrates a method in which a terminal indicates an uplinkwaveform to a base station using 2 bits reserved in one of the existinguplink MAC CEs according to an embodiment of the present disclosure.

FIG. 23A illustrates a method for indicating, by a base station, adynamic uplink waveform change to a terminal based on an RRC message asan indication method in an RRC layer for a control signaling operationfor a dynamic uplink waveform change indication according to anembodiment of the present disclosure.

FIG. 23B illustrates a method for feeding back an uplink waveformindicator by allowing a terminal to use an RRC message according to anembodiment of the present disclosure.

FIG. 24 illustrates an indication method for a base station to aterminal to carry UL_waveform_indicator information indicating an uplinkwaveform on fields such as MIB, SIB1, and SIB2 of system information asa method for indicating an uplink waveform by system information (SI)for a control signaling operation for a dynamic uplink waveform changeindication according to an embodiment of the present disclosure.

FIG. 25 illustrates an operation of calculating, by a terminal, a PHRand reporting the calculated PHR to allow a base station to perform ULscheduling based on the corresponding information according to anembodiment of the present disclosure.

FIG. 26 illustrates an operation of allocating an uplink resource andperforming scheduling by correcting a PH reception value and correctingP_max based on an uplink waveform as a reference in a PHR transmittedfrom a terminal and a waveform to be applied to an actual uplinktransmission.

FIG. 27 illustrates a structure of the terminal according to anembodiment of the present disclosure.

FIG. 28 illustrates a structure of the base station according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 28, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. When it is decidedthat a detailed description for the known function or configurationrelated to the present disclosure may obscure the gist of the presentdisclosure, the detailed description therefor will be omitted. Further,the following terminologies are defined in consideration of thefunctions in the present disclosure and may be construed in differentways by the intention or practice of users and operators. Therefore, thedefinitions thereof should be construed based on the contents throughoutthe specification.

Various advantages and features of the present disclosure and methodsaccomplishing the same will become apparent from the following detaileddescription of embodiments with reference to the accompanying drawings.However, the present disclosure is not limited to the embodimentsdisclosed herein but will be implemented in various forms. Theembodiments have made disclosure of the present disclosure complete andare provided so that those skilled in the art can easily understand thescope of the present disclosure. Therefore, the present disclosure willbe defined by the scope of the appended claims. Like reference numeralsthroughout the description denote like elements.

Further, it may be understood that each block of processing flow chartsand combinations of flow charts may be performed by computer programinstructions. Since these computer program instructions may be mountedin processors for a general computer, a special computer, or otherprogrammable data processing apparatuses, these instructions executed bythe processors for the computer or the other programmable dataprocessing apparatuses create means performing functions described inblock(s) of the flow charts. Since these computer program instructionsmay also be stored in a computer usable or computer readable memory of acomputer or other programmable data processing apparatuses in order toimplement the functions in a specific scheme, the computer programinstructions stored in the computer usable or computer readable memorymay also produce manufacturing articles including instruction meansperforming the functions described in block(s) of the flow charts. Sincethe computer program instructions may also be mounted on the computer orthe other programmable data processing apparatuses, the instructionsperforming a series of operation steps on the computer or the otherprogrammable data processing apparatuses to create processes executed bythe computer to thereby execute the computer or the other programmabledata processing apparatuses may also provide steps for performing thefunctions described in block(s) of the flow charts.

In addition, each block may indicate some of modules, segments, or codesincluding one or more executable instructions for executing a specificlogical function (s) Further, it is to be noted that functions mentionedin the blocks occur regardless of a sequence in some alternativeembodiments. For example, two blocks that are consecutively illustratedmay be simultaneously performed in fact or be performed in a reversesequence depending on corresponding functions sometimes.

Here, the term “˜unit” used in the present embodiment means software orhardware components such as FPGA and ASIC and the “˜unit” performs anyroles. However, the meaning of the “˜unit” is not limited to software orhardware. The “˜unit” may be configured to be in a storage medium thatmay be addressed and may also be configured to reproduce one or moreprocessor. Accordingly, for example, the “˜unit” includes componentssuch as software components, object oriented software components, classcomponents, and task components and processors, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuit, data, database, data structures, tables, arrays, andvariables. The functions provided in the components and the “˜units” maybe combined with a smaller number of components and the “˜units” or maybe further separated into additional components and “˜units.” Inaddition, the components and the “˜units” may also be implemented toreproduce one or more CPUs within a device or a security multimediacard.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. When it is decidedthat a detailed description for the known function or configurationrelated to the present disclosure may obscure the gist of the presentdisclosure, the detailed description therefor will be omitted. Further,the following terminologies are defined in consideration of thefunctions in the present disclosure and may be construed in differentways by the intention or practice of users and operators. Therefore, thedefinitions thereof should be construed based on the contents throughoutthe specification.

A power headroom refers to a difference between current transmissionpower of a terminal and maximum output power of the terminal, and theterminal may calculate the power headroom as shown in Equation 1 asgiven by:PH(i)=P _(CMAX)(i)−P _(Tx)(i)  (1)

The above Equation 1 refers to a power headroom value that the terminalcalculates in an i-th subframe of the terminal, which may be formed of adifference between transmission power P_(TX)(i) that the terminalactually uses for a transmission of uplink data and control informationand maximum output power P_(CMAX)(i) of the terminal. The P_(TX)(i) mayvary depending on whether to transmit the data information or thecontrol information or simultaneously transmit the data information andthe control information in the i-th subframe. The following Equation 2ais an example of the P_(Tx)(i) for the case of transmitting datainformation in the i-th subframe, and the following Equation 2b is anexample of the P_(TX)(i) for the case of transmitting the controlinformation in the i-th subframe:P _(TX)(i)=10 log₁₀(M _(PUSCH)(i))+P _(0-PUSCH)(j)+α(j)·Δ_(TF)(i)+f(i)[dBm]   (2a)

The above Equation 2a illustrates transmission power of a physicaluplink shared channel (PUSCH), which is a physical channel for thetransmission of the uplink data in the i-th subframe of the terminal.

At this time, P_(0_PUSCH) is a parameter consisting ofP_(0_NORMAL_PUSCH)+P_(O_UE_PUSCH), and is a value that the base stationinforms the terminal by higher layer signaling (RRC signaling).

In particular, P_(O_NORMAL_PUSCH) is a cell-specific value consisting of8-bit information and has a range of [−126, 24] dB.

In addition, P_(O_UE_PUSCH) is a UE-specific value consisting of 4-bitinformation and has a range of [−8, 7] dB. The cell-specific value istransmitted from the base station by cell-specific RRC signaling (SIB:System Information Block), and the UE-specific value is transmitted tothe terminal through dedicated RRC signaling.

At this time, j means a grant scheme of the PUSCH. More specifically,j=0 means a semi-persistent grant, j=1 means a dynamic scheduled grant,and j=2 means a PUSCH grant for a random access response. Meanwhile,α(j) is a value for compensating for a path-loss. In the case of α(0)and α(1), the base station cell-specifically informs all the terminalsof one of {0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1} by 3-bit information. Avalue of α(2)=1 is used.

PL is the path-loss value calculated by the terminal and is calculatedby received power of a cell-specific reference signal (CRS) of adownlink channel that the base station transmits. Δ_(TF)(i) is a valuerelated to MCS, and f(i) is a parameter for performing power control ina closed-loop:P _(TX)(i)=P _(0_PUCCH)+PL+h(n _(CQI) ,n _(HARQ) ,n_(SR))+Δ_(F-PUCCH)(F)+Δ_(TxD)(F′)+g(i) [dBm]  (2b)

The above Equation 2b shows transmission power of a physical uplinkcontrol channel (PUCCH), which is a physical channel for thetransmission of the uplink control information in the i-th subframe ofthe terminal.

At this time, P_(0_PUCCH) is a parameter consisting ofP_(0_NORMAL_PUCCH)+P_(O_UE_PUCCH), and is a value that the base stationinforms the terminal by higher layer signaling (RRC signaling).

In particular, P_(O_NORMAL_PUCCH) is a cell-specific value consisting of8-bit information and has a range of [−126, 24] dB.

In addition, P_(O_UE_PUCCH) is a UE-specific value consisting of 4-bitinformation and has a range of [−8, 7] dB. The cell-specific value istransmitted from the base station by cell-specific RRC signaling (SIB),and the UE-specific value is transmitted to the terminal throughdedicated RRC signaling. Meanwhile, unlike the transmission powercontrol of the PUSCH, α(j) compensating for the path-loss is not used inthe transmission power control of the PUCCH.

Similar to the transmission power control of the PUSCH, the PL which isthe path-loss value calculated by the terminal is calculated by receivedpower of the CRS of a downlink channel that the base station transmits.The Δ_(F_PUCCH)(F) is transmitted to the terminal by the higher layersignaling (cell-specific or UE-specific RRC signaling) and is a valuevarying depending on a format of the PUCCH.

Δ_(TxD)(F′) is transmitted to the terminal by the higher layer signaling(cell-specific or UE-specific RRC signaling) when the PUCCH istransmitted to the 2-antanna ports (i.e., space frequency block code(SFBC)) and is a value which may vary depending on the format of thePUCCH.

h(n_(CQI), n_(HARQ), n_(SR)) are other values depending on the format ofthe PUCCH, where n_(CQI) denotes the number of bits used for feedback ofchannel quality information, n_(HARQ) denotes the number of bits usedfor feedback of HARQ-ACK/NACK, and n_(SR) is 0 or 1 as a bit used forfeedback of the scheduling request (SR). g(i) is a parameter forperforming power control in a closed-loop, and the base station mayUE-specifically correct the transmission power of the PUCCH.

On the other hand, P_(CMAX)(i) representing the maximum output power ofthe terminal in the i-th subframe has a value in the range of thefollowing Equation 3a and may be calculated by the terminal based on thefollowing Equation 3b and Equation 3c as given by:P _(CMAX_L) ≤P _(CMAX) ≤P _(CMAX_H)  (3 a)

In the above Equation 3a, P_(CMAX_L) means a small value of P_(CMAX),and may be calculated by the terminal based on the following Equation3b. P_(CMAX_H) means a large value of the P_(CMAX), and may becalculated by the terminal based on the following Equation 3c as givenby:P _(CMAX_L)=min{P _(EMAX) −ΔT _(C) ,P _(PowerClass)−Max{MPR+AMPR+ΔT_(IB) +ΔT _(C),PMPR}}   (3b)P _(CMAX_H)=min{P _(EMAX) ,P _(PowerClass)}  (3c)

In the above Equations 3b and 3c, P_(EMAX) is the maximum transmissionpower that the terminal may use for uplink transmission in a specificcell, and is a value that the base station informs by the UE-specificRRC signaling. P_(PowerClass) is a value corresponding to a power classof the terminal and may correspond to capability of the terminal (e.g.,23 dBm). A maximum power reduction (MPR) may reflect the amount offrequency resources (the number of RBs, the number of resource blocks)and modulation allocated to the terminal for the transmission of theuplink data and control channel. An additional maximum power reduction(AMPR) is a value which is based on an adjacent channel leakage ratio(ACLR) and spectral emission requirements. ΔT_(IB) is a tolerance valuedepending on a combination of bands in which communications are made,ΔT_(C) is a value varying depending on the aggregated channel bandwidthand the guard band, and a power amplifier-maximum power reduction (PMPR)is a parameter for complying with regulations in multi-RAT environment.

The terminal reports the power headroom value calculated based on theabove Equation 1 to the base station, and the base station may use thepower headroom value to optimize the system operation.

For example, if the power headroom value that the specific terminalreports to the base station is positive, the base station may increase asystem yield by allocating more resource blocks (RBs) to thecorresponding terminal. Unlike this, if the power headroom value thatthe specific terminal reports to the base station is negative, the basestation may allocate less resources to the corresponding terminal orreduce the transmission power of the corresponding terminal by atransmission power control command. In this way, it is possible toreduce unnecessary power consumption of the corresponding terminal or toprevent performance deterioration in a reception signal of the basestation due to an in-band emission.

On the other hand, in a system using beamforming, a mismatch between thedownlink channel state and the uplink channel state may be greatlyincreased as compared with the system not using beamforming.

(1) For the first reason, a transmission beam gain for downlinktransmission of the base station and a reception beam gain for uplinkreception of the base station may be different from each other.Similarly, the reception beam gain for the downlink reception of theterminal and the transmission beam gain for the uplink transmission ofthe terminal may be different from each other. This is because thenumber of panels of the base station transmitting antenna may bedifferent from the number of the panels of the base station receivingantenna and similarly, the number of panels of a terminal transmittingantenna may be different from the number of panels of a terminalreceiving antenna. For example, the base station uses transmission powerof 46 dBm for the downlink transmission, but the terminal can usetransmission power of 23 dBm much less than the transmission power ofthe downlink transmission. Therefore, the coverage of the downlinksignal and the coverage of the uplink signal may be different from eachother.

In order to solve the above problem, the number of panels of thereceiving antenna of the base station is increased (the number of panelsof the receiving antenna is increased compared with the number of panelsof the transmitting antenna of the base station), thereby increasing thereception beam gain of the base station to secure the coverage of theuplink signal. In addition, the number of panels of the transmittingantenna of the terminal is increased (the number of panels of thetransmitting antenna is increased compared with the number of panels ofthe receiving antenna of the terminal) to increase the transmission beamgain of the terminal, thereby securing the uplink coverage.

(2) The second reason why the mismatch between the downlink channelstate and the uplink channel state may be increased in the system usingbeamforming is that there may be different beam gains depending on thebeam used by the base station and the beam-pair used by the terminal.For example, it is assumed that the base station uses N beams 1, 2, . .. , N and the terminal uses M beams 1, 2, . . . , M. The terminal mayassume that a transmission beam 3 and a reception beam 1 of the basestation may be the best beam, which is assumed to be the downlink bestbeam-pair. At this time, the best beam means the beam having the largestreceived signal. However, in terms of the reception of the base station,the transmission beam 2 of the terminal and the reception beam N of thebase station may be the best beam, which is assumed to be the uplinkbest beam-pair. As described above, since the beam gains used forforming the downlink best beam-pair and the uplink best beam-pair may bedifferent from each other, the mismatch may occur between the downlinkchannel state and the uplink channel state. As another example, even ifthe beam gains of the downlink best beam-pair and the uplink bestbeam-pair are the same, for a flexible beam operation, the base stationmay instruct the specific terminal to transmit the uplink data and thecontrol information through an uplink second best beam-pair or an uplinkthird best beam-pair, not through the uplink best beam-pair. In thiscase, the mismatch between the downlink channel state and the uplinkchannel state may be increased.

(3) The third reason why the mismatch between the downlink channel stateand the uplink channel state may be increased in the system usingbeamforming is that the base station and the terminal may use differentbeam widths when a synchronization signal, a control channel and a datachannel are transmitted. More specifically, in the beamforming system,the synchronization signal, the control channel, and the data channelmay be transmitted by performing beam sweeping. At this time, when thesynchronization signal and the control channel (for example, physicalbroadcast channel (PBCH)) requiring broadcast or multicast aretransmitted using a narrow beam width, the entire cell may be covered bythe beam having the narrow beam width, such that the time required forthe beam sweeping may be increased. Therefore, the synchronizationsignal and the control channel requiring the broadcast or multicasttransmission needs to be transmitted using a beam having a wider beamwidth. In the present disclosure, transmitting the channel may meantransmitting the information through the channel, which may beinterchangeably used.

On the other hand, since the control channel (for example, physicaluplink control channel (PUCCH)) and the data channel (for example,physical uplink shared channel (PUSCH)) that need to be transmitted bythe unicast are transmitted to the specific terminal, the controlchannel and the data channel need to be transmitted using the beamhaving the narrower beam width to secure the coverage and reduce theinterference. In addition, when the downlink channel measurement isperformed by a wider beam and the uplink transmission is performed by anarrower beam, the mismatch between the downlink channel state and theuplink channel state may be increased.

When the mismatch between the downlink channel state and the uplinkchannel state is increased in the beamforming system due to variousreasons described above, the base station may have a serious problem inoperating the system using the power headroom information calculated bythe terminal over the downlink channel as in the above Equation 1. Forexample, if the power headroom value of the specific terminal ispositive, the base station may increase the number of resources to beallocated to the terminal (i.e., increase the M_(PUSCH) of the aboveEquation 2a), which may be the same as increasing the transmission powerof the terminal. At this time, there may be the case in which the actualchannel state of the uplink may mismatch the downlink channel stateapplied when the terminal calculates the power headroom, which mayresult in using less transmission power than the transmission power thatthe actual terminal may use. Therefore, there may be a problem in thatthe coverage of the uplink signal cannot be ensured.

As another example, when the actual channel state of the uplinkmismatches the downlink channel state applied when the terminalcalculates the power headroom, the transmission power higher than thetransmission power that the actual terminal can use may be used. Thismay cause the unnecessary power consumption of the terminal. Inaddition, there may be the case in which the terminal transmits a signalat power greater than the terminal's maximum transmission output power(power greater than P_(CMAX) in [Equation 1]). In this case, performanceof an error vector magnitude (EVM) of signals that the terminaltransmits on the uplink is degraded, thus reliability of the receivedsignal of the uplink signal cannot be secured. In addition, when thetransmission power higher than the transmission power that the actualterminal may transmit is used, if the terminal may be located close tothe base station, the transmission power of the corresponding terminalexceeds a dynamic range of the base station receiver, thus interferencemay occur in the uplink signals of other terminals that the base stationmay receive (In-band emission). Therefore, it may be a main cause ofdeteriorating system performance.

In the beamforming system, as described above, the mismatch problembetween the downlink channel and the uplink channel is increased due tothe difference between the beam gains used in the downlink and theuplink, thus the reliability of the power headroom information thatterminal transmits to the base station may be degraded. Therefore, asolution is needed to solve this problem.

As one embodiment for solving the first reason for increasing themismatch between the downlink channel and the uplink channel describedabove, the base station may measure (or predict) the base station's owntransmitting beam gain and receiving beam gain during a capabilitynegotiation process between the base station and the terminal, andinform the terminal of the measured information. The terminal may alsomeasure (or predict) the terminal's own transmitting beam gain andreceiving beam gain and may inform the base station of the measuredinformation. The terminal may apply the information to the calculationof the power headroom of the above Equation 1. More specifically, whenthe path-loss (PL) of the above Equations 2a and 2b is predicted, theterminal compares the transmission beam information of the base stationtransmitted from the base station with the reception beam information ofthe base station and uses the larger value of the transmission beaminformation and the reception beam information to predict the path-lossor uses the smaller value (or larger value) of the transmission beaminformation and the reception beam information or an average of the twovalues to predict the path-loss.

As another example, the base station may utilize the information on thetransmission beam gain and the reception beam gain of the terminalreported from the terminal to predict the state of the uplink channel.At this time, the terminal calculates the power headroom value in astate in which the transmission beam gain and the reception beam gain ofthe base station are unknown, and reports the calculated power headroomvalue to the base station. The base station may re-interpret the powerheadroom information transmitted from the terminal using the informationon the transmission beam gain or receiving beam gain of the terminalreported from the terminal in the capability negotiation and theinformation on the transmission beam gain or receiving beam gain of thebase station itself. That is, the transmission beam or receiving beamgains of the base station or the terminal may be combined with the powerheadroom value that the specific terminal transmits, to more accuratelydetermine whether to increase the number of resources to be allocated tothe corresponding terminal (whether to increase the transmission power)or whether to reduce the number of resources to be allocated to thecorresponding terminal (whether to reduce the transmission power).

However, in the beamforming system, it is necessary to perform beammanagement for the transmission or reception beams of the base stationand the transmission or reception beams of the terminal for theefficient beam operation. Therefore, as in the second and third reasonsfor increasing the mismatch between the downlink channel and the uplinkchannel described above, the transmission/reception beam gains of thebase station and the terminal may be dynamically changed according tothe beam width and the beam-pair that are operated in the base stationand the terminal. In such a situation, only the method for exchangingthe beam gain information through the capability negotiation between thebase station and the terminal may not increase the accuracy of the powerheadroom information. Therefore, in the beamforming system, it isnecessary to transmit the power headroom information considering thebeam management, which will be described below in detail.

FIG. 1 schematically illustrates a structure of a (5G, NR) communicationsystem according to an embodiment of the present disclosure, and is anexample of a configuration of an MME, an S-GW, and a 5G base station(gNB).

Referring to FIG. 1, the wireless communication system is configured toinclude a plurality of base stations (BSs) 105, 110, 115 and 120, amobility management entity (MME) 125, a serving gateway (S-GW) 130. Theuser terminal (user equipment (UE) or a terminal 135) may access anexternal network through the base station and the S-GW.

FIG. 2 schematically illustrates the structure of the (5G, NR)communication system according to the embodiment of the presentdisclosure, and is an example of a configuration of CU, DU, and TRxP.

The central unit (CU) performs an operation of controlling acommunication protocol layer above the PDCP. In the data units (DUs) 220and 230, the DU becomes a unit of a cell in a structure in which MAC andPHR protocol layers starting from the RLC are operated, and is anexample of a structure in which a plurality of transmitting andreceiving points (represented by transmission and receiving point (TRxP)or TRP) within the same DU is operated.

FIG. 3 illustrates an example of an operation of calculating andtransmitting power headroom information for an uplink power control.

A definition and an operation for beam-based PHR are not designed forPHR transmission in the existing LTE (omnidirectional). Therefore, inthe beamforming transmission, when the PHR transmission operation isperformed by mapping to the serving beam, there is a problem in that adelay occurs in the transmission of the PHR information according to adelay corresponding to the beam switch.

That is, when the PHR is reported according to the generation of the PHRtriggering event based on the Pathloss change in the serving beam, thedelay occurs. As the concrete operation example, the delay occurs in thecase of determining whether to generate the PHR triggering event basedon the pathloss change as a previous serving beam reference (beam 1)until the beam change is completed during the operation of changing aserving beam from a previous source beam (beam 1) to a target beam (beam2) (301). In addition, the PHR transmission delay is additionallygenerated by a UL scheduling procedure for the PHR transmission afterdetecting the PHR triggering event. Finally, the base station canreceive the PH information and then allocate UL resources for uplinkdata transmission based on the PH information.

Therefore, it is physically possible to perform the uplink transmissiondirectly from the completion of the beam switch. In other words, it ispossible to realize 0 ms interruption time in terms of the uplink datatransmission. When the PHR is transmitted by the existing LTE operation,the delay occurs and therefore an error of a UL power control may occurdue to the lack of PH information upon the transmission of the initialuplink, thereby causing the deterioration in the uplink transmissionperformance. In addition, the transmission delay problem occurs when theterminal starts the UL transmission by allocating the UL resource afterthe base station receives PH.

Since the beam change operation is performed after a certain time (beamswitching timer) after the base station determines the beam switch (beamchange) after the measurement report of the terminal, the path-losschange by the beam change can be predicted by the operation procedure.

FIG. 4 illustrates an example of the uplink beam change.

When the beam of the base station which is the uplink reception beam ischanged, if the beam 410 and the target beam 420 exists within the sameTRxP, since the source beam and the target beam exist within the TRxPsfor the terminal and the base station, there is a high probability thatthe physical locations are the same and the path-loss of the sourcebeam-pair and the path-loss of the target beam-pair are similar to eachother.

FIG. 5 illustrates another example of the uplink beam change.

When the beam of the base station which is the uplink reception beam ischanged, if the current serving beam 501 and the target beam 502separately exist in another TRxP, since the location of the terminal isthe same, but the TRxPs, which are points at which the base station (DU)actually performs the transmission and reception, are different, thephysical location is different, so the Pathlosses of the sourcebeam-pair and the target beam-pair are highly likely to be changed.

Therefore, there is a need for a design and a method for a PHR format, aPHR triggering event, and control signaling for establishing the same asa method for transmitting a new PHR for supporting new transmissionenvironment, beamforming transmission, and a network structure TRxPconfigured of CU-DU-TRxP.

FIG. 6 illustrates an example of an operation of setting the number ofPHs included in the PHR for the transmission of the power headroominformation. As the PHR transmission method, there are (1) a method fortransmitting a single PH, (2) a method for transmitting a plurality ofPHs per beam, and (3) a method for transmitting a plurality of PHs perTRxP.

Option 1] The single PH operation per terminal is a method for operatinga single PH per RRC link between a terminal and a base station.

Option 2] A method for operating a plurality of PHs per beam includes abase station configuration, a PHR format, a terminal per beam PHcalculation and transmission operation.

Option 3] A method for operating a plurality of PHs per TRP includes abase station configuration, a PHR format, a terminal per TRP PHcalculation and transmission operation.

As mounting information for a PHR configuration for supporting one RRCtransmission link, a situation in which additional information isrequired in addition to single power headroom (PH) includes thefollowing conditions.

(1) multiple serving beam pairs in simultaneous: a situation of anetwork or a base station supporting a function of performing uplinktransmission by simultaneously operating a plurality of serving beams.

(2) multiple UL serving beam pair across TRxP: even in a situation ofthe network or the base station supporting the function of performingthe uplink transmission by simultaneously operating the plurality ofserving beam, in particular, when the current serving beam and thetarget beam of the base station, which is the uplink reception beam,separately exist in another TRxP, since the location of the terminal isthe same but the TRxPs, which are a point where the base station (DU)actually transmits and receives the source beam and the target beam, aredifferent, the physical locations are different and thus the PHinformation of the corresponding source beam-pair and target beam-pairare highly likely to be different; or.

(3) dynamic Rx beam change from eNB for the UL transmission: when theterminal does not know the reception beam (base station reception beam)information upon the uplink transmission in the case in which the basestation dynamically changes the uplink reception beam, a method forcalculating PH for a plurality of candidate beams and transmitting thecalculated PH is provided.

This case includes a case in which the base station performs uplinkscheduling dynamically or a case where a fast uplink transmission may beperformed since a supported service requires low latency performance.That is, after the terminal transmits the PH, the base station transmitsthe UL grant for the resource allocation of the uplink transmission andthen performs the uplink data transmission. However, the terminal mayknow the UL receiving beam information of the base station upon thetransmission of the PH to transmit the single PH. If a single PH istransmitted based only on the UL receiving beam information of thecorresponding base station, there is a problem in that the base stationcannot update the UL receiving beam having a better beam gain becausethe channel environment is changed or the UL receiving beam even whenthe corresponding beam gain is changed.

The method includes the case in which the serving beam and the targetbeam exist within the same TRxP. Unlike this, when the current beam andthe target beam of the base station separately exist in another TRxPsince the location of the terminal is the same, but the TRxPs, which arepoints at which the base station (DU) actually transmits and receivesthe source beam and the target beam, are different. For this reason, amethod for transmitting information on PH based on a downlinktransmission beam-pair and information on a plurality of PHs based onuplink transmission beam-pair to a PHR report that a terminal transmitsis provided.

(4) DL/UL beam mismatch (across TRxP): there may be the case in whichthe current serving beam and the target beam exist within the same TRxPwhen the downlink transmission beam-pair and the uplink transmissionbeam-pair are different, but in particular, when the current servingbeam and the target beam of the base station, which is the uplinkreception beam, separately exists in another TRxP, since the location ofthe terminal is the same, but the TRxPs, which are points at which thebase station (DU) actually transmits and receives the source beam andthe target beam are different, a method for transmitting information ona PH based on a downlink transmission beam-pair and information on aplurality of PHs based on uplink transmission beam-pair to a PHR reportthat a terminal transmits is provided.

(4-1) When the base station informs the terminal of the uplink receptionbeam (base station reception beam) information in advance, a method fortransmitting a single PH corresponding to a corresponding uplinktransmission beam-pair is provided; and

(4-2) When the terminal does not know the uplink reception beam (basestation reception beam) information upon the uplink transmission, amethod for calculating PHs for a plurality of candidate beams andtransmitting the calculated PHs is provided.

The operation for setting the number of PHs included in the PHR for thetransmission of the power headroom information will be described in moredetail. The base station includes an operation of dividing a situationrequiring the above-described additional PH information to perform thePHR configuration, that is, an operation of configuring thecorresponding PHR related parameters for the operation of the pluralityof PHs per next beam and the operation of the plurality of PHs per TRxP(1)(2) when the plurality of uplink beam-pairs are used for thetransmission and (3)(4) when the base station dynamically changes theuplink reception beam.

Option 1] The single PH operation per terminal is a method for operatinga single PH per RRC link between a terminal and a base station.

If it is determined that the base station does not include the operationof dividing a situation requiring the above-described additional PHinformation to perform the PHR configuration, that is, does notcorrespond to (1)(2) the case in which the plurality of uplinkbeam-pairs are used for the transmission and (3)(4) the case in whichthe base station dynamically changes the uplink reception beam, theoperation of the single PH per terminal includes a method for operatinga single PH per RRC link between the terminal and the base station.

Option 2] As a method for operating a plurality of PHs per beam, theremay be the base station configuration control signaling, the PHR format,the terminal per beam PH calculation and transmission operation.

However, this beam-based PH operation and the plurality of PHtransmissions can cause a control burden, and therefore, a method foroperating a plurality of PHs per TRxP based on the channel similaritybetween beams within the same TRxP is provided.

Option 3] A method for operating a plurality of PHs per TRxP includes abase station configuration, a PHR format, a terminal per TRP PHcalculation and transmission operation.

In more detail, when the base station transmits RRC (re)configurationcontrol signaling to the terminal, the following embodiments include anoperation of indicating the number of PHs included in the PHR that theterminal transmits.

Option 1) When the number of PH included in the PHR of the terminal isone, the terminal may calculate and operate the single PH based on theserving beam-pair. As a method for calculating and operating, by aterminal, a single PH, there are a method for transmitting a single PHto a PHR report and a method for selecting information on whether totransmit one PH and the corresponding PH. The embodiment of theoperation may use a method for perform PHR transmission for PHinformation on one beam-pair received by Best RSRP.

Option 2) As a method for calculating and operating PH based on eachbeam-pair, there is a method for transmitting a plurality of PHs to aPHR report. A method for selecting information (PH for N beams) on howmany PH is transmitted and the corresponding PH includes the followingembodiment.

(2-1) N beams (method for transmitting a PHR for Best N Beam-pairsreceived by Best RSRP) in descending order of signal strength (forexample, including RSRP and RSRQ) of beam

(2-2) N beams in an ascending order of the signal strength (for example,including RSRP and RSRQ) of the beam

(2-3) N beams or N_1 beams (including an operation of changing thenumber of PH target beams depending on the number of beams larger thanthe average value) equal to or greater than the average value of thesignal intensity (for example, including RSRP and RSRQ) of the beam

(2-4) An operation of calculating and transmitting PH values for randomN beams regardless of the signal strength (for example, including RSRPand RSRQ) of the beam is provided.

Option 3) As a method for calculating and operating a PH based on eachTRxP, there are a method for transmitting a plurality of PHs to a PHRreport, a method for transmitting information on how many PH istransmitted, a method for selecting the corresponding PH (for example,transmission of the PHR for Best N TRxPs received by Best RSRP), and amethod for informing information on Beam group corresponding to TRxP(for example, information on TRxP=1 including base station beam indexes1, 2, 3, 4 and TRxP=2 including base station beam indexes 5, 6, 7, 8).The method for selecting and transmitting PH includes the followingmethod.

(3-1) An operation of calculating and transmitting PH values forrepresentative vales of each TRxP corresponding to N beams (method fortransmitting a PHR for best N beam-pairs received by Best RSRP) in adescending order of the signal strength (for example, including RSRP andRSRQ) of the beam is provided

(3-2) An operation of calculating and transmitting PH values forrepresentative values of each TRxP corresponding to N beams in anascending order of the signal strength (for example, including RSRP andRSRQ) of the beam is provided.

(3-3) An operation of calculating and transmitting PH values forrepresentative values of each TRxP corresponding to N beams or N_1 beams(including the operation of changing the number of PH target beamsdepending on the number of beams larger than the average value) equal toor greater than the average value of the signal strength (for example,including RSRP and RSRQ) of the beam is provided.

(3-4) An operation of calculating and transmitting PH values forrepresentative values of each TRxP corresponding to random N beamsregardless of the signal strength (for example, including RSRP and RSRQ)of the beam is provided.

When transmitting the RRC (re)configuration control signaling to theterminal, the base station may include the information on an event fortriggering the single PHR report, in which an event 620 for triggeringthe single PHR report includes the following embodiment.

(1) When NServing beam changes are expected.

(2) When related information is changed when calculating PH per Beam.

(3) When related information is changed when calculating PH per TRxP.

In more detail, the method for calculating and operating PH based onbeam-pair among the conditions for the transmission of the powerheadroom information considering event-based beamforming may bevariously defined as follows based on each beam reception signal.

(1) When the path-loss of at least one of the beams included in the lastpower headroom information that the terminal transmits to the basestation is changed to a specific threshold value or more.

(2) When the path-loss for the best beam (beam having the largest signalstrength of the beam) among the beams included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(3) When the path-loss for the worst beam (beam having the smallestsignal strength of the beam) among the beams included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(4) When the path-loss for X or more beams among the beams included inthe last power headroom information that the terminal transmits to thebase station (in a descending order of the signal strength of the beam)is changed to a specific threshold value or more.

(5) When the path-loss for Y or more beams among the beams included inthe last power headroom information that the terminal transmits to thebase station (in an ascending order of the signal strength of the beam)is changed to a specific threshold value or more.

(6) When the path-loss of all of the beams included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(7) When the average value for the path-loss of the beams included inthe last power headroom information that the terminal transmits to thebase station is changed to a specific threshold value or more.

(8) If z ms has elapsed after the base station instructed the uplink ordownlink beam to be changed (z is a timer expiration value, and the basestation provides information to the terminal through the RRCconfiguration).

(9) When the beam ID (or beam IDs) configured by the base station forbeam management and the beam ID (or beam IDs) measured by the terminalare different from each other.

(10) When the downlink beam measurement report of the terminal isconfigured of the uplink data channel (PUSCH) rather than the uplinkcontrol channel (PUCCH).

A method for setting a representative value based on a received signalfor a beam group of TRxP in an operation based on the received signalfor the beam group of the TRxP among the events for triggering theterminal PHR report includes the following embodiment.

(3-1) An operation of setting K_1 beam to be a representative value ofTRxP in a descending order of the signal strength (e.g., including RSRPand RSRQ) of the beam within the beam group of the TRxP is provided.

(3-2) An operation of setting K_1 beam to be a representative value ofTRxP in an ascending order of the signal strength (e.g., including RSRPand RSRQ) of the beam within the beam group of the TRxP is provided.

(3-3) An operation of setting K_1 beam to be a representative value ofTRxP based on an average value of the signal strength (e.g., includingRSRP and RSRQ) of the beam within the beam group of the TRxP isprovided.

(3-4) An operation of setting random K_1 beam to be a representativevalue of TRxP regardless of the signal strength (e.g., including RSRPand RSRQ) of the beam within the beam group of the TRxP is provided.

Here, the number of K_1 can be plural or single (one).

In addition, the method for calculating and operating PH based on eachTRxP based on the received signal for each TRxP beam group like Option3) among the power headroom information transmission considering theevent-based beamforming may be variously defined as follows based on thereceived signal for the beams of each TRxP.

(11) When the path-loss of at least one of theTRxPs included in the lastpower headroom information that the terminal transmits to the basestation is changed to a specific threshold value or more.

(12) When the path-loss for the best TRxP (beam having the largestsignal strength of the TRxP) among the TRxPs included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(13) When the path-loss for the worst TRxP (beam having the smallestsignal strength of the beam) among the TRxPs included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(14) When the path-loss for X or more TRxPs among the TRxPs included inthe last power headroom information that the terminal transmits to thebase station (in a descending order of the signal strength of the beam)is changed to a specific threshold value or more.

(15) When the path-loss for Y or more TRxPs among the beams included inthe last power headroom information that the terminal transmits to thebase station (in an ascending order of the signal strength of the TRxP)is changed to a specific threshold value or more.

(16) When the path-loss of all of the TRxPs included in the last powerheadroom information that the terminal transmits to the base station ischanged to a specific threshold value or more.

(17) When the average value for the path-loss of the TRxPs included inthe last power headroom information that the terminal transmits to thebase station is changed to a specific threshold value or more.

(18) If z ms has elapsed after the base station instructs the uplink ordownlink beam to be changed (z is a timer expiration value, and the basestation provides information to the terminal through the RRCconfiguration).

(19) When the beam ID (or beam IDs) configured by the base station forbeam management and the TRxP ID (or TRxP IDs) measured by the terminalare different from each other.

(20) When the downlink TRxP measurement report of the terminal isconfigured of the uplink data channel (PUSCH) rather than the uplinkcontrol channel (PUCCH).

Also, under the above conditions, the terminal may request thetransmission of the power headroom information and transmit the powerheadroom information as follows.

When the terminal requests the transmission of the power headroominformation and the base station confirms the request or allocates theuplink resource, the terminal transmits the power headroom information.

When the terminal requests the transmission of the power headroominformation and the base station instructs the power headroominformation for the specific beam or the beams (or reference signalresource location, port information or the like corresponding thereto)to be transmitted, the terminal transmits the power headroom informationaccordingly.

Also, if the base station directly instructs the power headroominformation for the specific beam or the beams (or reference signalresource location, port information or the like corresponding thereto)to be transmitted, the terminal may transmit the power headroominformation accordingly.

As the method for transmitting a PHR, (1) a method (630) fortransmitting a single PH, (2) a method (640) for transmitting aplurality of PHs per beam, and (3) a method (650) for transmitting aplurality of PHs per TRxP include the following operations include thefollwing operation.

(1) As a method for detecting and operating, by a terminal, acorresponding PHR transmission mode, there are the following methods.

As a method for transmitting, by a base station, beam group information,information such as network architecture reflection (CU-DU-TRxP), andPHR based on PHR pre-configuration, the related configuration, of (1)the method for transmitting a single PH, (2) a method for transmitting aplurality of PHs per beam, and (3) a method for transmitting a pluralityof PHs per TRxP, a PHR format, and a method for calculating andtransmission a PH of modes are configured in advance and a method forapplying and operating by a terminal, a PHR transmission mode based onthe same is provided.

(2) As a method for detecting and operating, by a base station, acorresponding PHR transmission mode, there are the following methods.

As a method for transmitting, by a base station, information on PHRpre-configuration based (beam group information) network architecturereflection (CU-DU-TRxP) or the like and a PHR at the time of changinginformation as needed, the related configuration of (1) the method fortransmitting a single PH, (2) the method for transmitting a plurality ofPHs per beam, and 3) the method for transmitting a plurality of PHs perTRxP, the PHR format, and the method for calculating and transmission aPH of mode are configured and updated by the RRC (re)configuration and amethod for applying and operating by a terminal, a PHR transmission modebased on the same is provided.

(2-1) A method in which a base station transmits whether to change TRxPto a terminal by a TRxP change indication based on (e.g., best N) beammeasurement reports that the terminal feeds back or explicitly transmitsa network initiated PHR request; and a method in which a terminalreceiving the same transmits a PHR are provided.

(2-2) As another method, the operation of transmitting, by a terminal, aPHR on which information on a plurality of PHs is included (per beam orTRxP), and selecting, by a base station, the information on the PHs toreflect the information on the PHs on a power control for a transmissionof uplink data is provided.

Also, (1) As a method for adding a serving beam(s) change event, amethod defined as the following Table 1 is provided. That is, a standarddocument may have contents as shown in Table 1. However, the followingcontents are only exemplary embodiments, and the method of adding theserving beam change event can be defined in various ways.

As an advantage of the PHR triggering when the serving beam(s) index ischanged, it is possible to quickly trigger the PH by changing theserving beam. However, as the uplink transmission for the PHRtransmission by the terminal increases, the control burden and powerconsumption for the PHR transmission increase (whenever the serving beamchange, PHR is triggered; frequent PHRs and unnecessary controloverhead.)

TABLE 1 NR specification A Power Headroom Report (PHR) shall betriggered if any of the following events occur:   prohibit PHR-Timerexpires or has expired, and the path loss has changed more than  dl-PathlossChange dB for at least one activated Serving Cell of anyMAC entity   which is used as a pathloss reference since the lasttransmission of a PHR in this   MAC entity when the MAC entity has ULresources for new transmission;   Change of the Serving Beam(s)   Whenthe MAC entity has UL resources for new transmission, and the followingis   true in this TTI for any of the change of Serving Beam(s) of anyMAC entity with   configured uplink:

(2) In addition, a method for setting a separate short prohibit timerapplied for changing a serving beam is provided. Make new the prohibittimer shorter or zero when the serving beam is changed.

As an operation method for prohibitPHR-Timer_beam configuration, inaddition to the setting of legacy prohibitPHR-Timer value, a method forseparately setting prohibitPHR-Timer_beam to be applied at the time ofchanging serving beam as the following Table 2 is provided.

TABLE 2 NR specification A Power Headroom Report (PHR) shall betriggered if any of the following events occur:   prohibit PHR-Timerexpires or has expired and the path loss has changed more than  dl-PathlossChange dB for at least one activated Serving Cell of anyMAC entity which is   used as a pathloss reference since the lasttransmission of a PHR in this MAC entity when   the MAC entity has ULresources for new transmission;   Change of the Serving Beam(s)    prohibitPHR-Timer_beam expires or has expired, and the path loss haschanged     more than dl-PathlossChange dB for at least one activatedServing Cell of any     MAC entity which is used as a pathloss referencesince the last transmission

3) As another method, a prohibit timer exception operation and anoperation of newly setting a path-loss threshold when suddenly changinga beam gain and a path-loss are provided. (Make new path loss thresholdto ignore prohibit timer for bblockage (NLOS) or beam change)

As an operation method of dl-Pathloss_Change beam configuration, inaddition to setting of a legacy dl-PathlossChange value, a method forseparately configuring dl-Pathloss_Change beam performing the prohibittimer exception operation at the time of transmitting beamforming and anoperation of triggering a PHR event based on the setting if a path-lossis changed above dl-Pathloss_Change beam within the prohibit timer areprovided.

An example of setting new parameters for the new PHR triggering eventand the related configuration is as the following Table 3.

TABLE 3 PHR triggering event and configuration Periodic_timer {sf10,sf20, sf50,sf100, sf200, sf500, sf1000, infinity} ProhibitPHR_timer {sf0, sf10, sf20, sf50, sf100, sf200, sf500, sf1000}ProhibitPHR_timer_beam {sf0, sf10, sf20, sf50, sf100, sf200, sf500,sf1000} dl-Pathlosschange {dB1, dB3, dB6, infinity}dl-Pathlosschange_beam{dB1, dB3, dB6, adB9, dB12, dB15, dB18, dB30,infinity}

FIGS. 7 to 12 illustrate an example of an operation of newly introducinga PHR triggering event related to a beam change and reducing a delay intransmitting the corresponding PHR. The concrete contents will bedescribed below.

Since beam mutuality is maintained between the downlink beam-pair andthe uplink 1 beam-pair, the base station may measure the uplink beam ofthe terminal and apply the measured uplink beam to the downlink beammanagement. The downlink beam management instruction of the base stationmay be made periodically or non-periodically. When the base stationperiodically instructs the beam management, the base station may provideinformation on a reference signal (RS) transmission for the measurementof the uplink beam to the terminal in order to measure the uplink beamthat the terminal transmits. For example, the base station may informthe terminal of a time resource (e.g., slot or subframe index, symbolindex within a slot or a subframe, or the like) and a frequency resource(e.g., a bandwidth for a sounding reference signal (SRS) transmission)for the sounding reference signal (SRS) transmission for the measurementof the uplink beam of the terminal.

When instructing the beam management periodically, the base station mayinform the terminal of the time-frequency resources for the SRStransmission through the RRC. The terminal receiving the time-frequencyresources forms different uplink beams by the number of beams that thebase station instructs and transmits the uplink SRS. Meanwhile, the basestation may instruct the terminal to non-periodically perform thedownlink beam management. In this case, the base station may use aspecific field within downlink DCI (downlink control information) oruplink DCI to trigger the beam management instruction. That is, specificX bits in the DCI may inform the terminal that the RS (e.g., SRS) forthe measurement of the uplink beam may be transmitted based on thecurrent subframe (subframe in which the downlink DCI is transmitted) orafter K subframe based on the current subframe. At this time, the basestation informs the terminal of the number of RS symbols used for themeasurement of the uplink beam, the symbol position where the RS istransmitted (e.g., the last symbol of the slot or the subframe or thelast second symbol), or two information by the DCI. Such information maybe related to how many uplink beams the terminal may use to perform theuplink transmissions.

For example, the downlink beam management information that the basestation transmits to the terminal may include information on how manybeams the terminal forms and transmits. For example, assume that thebase station may measure four uplink beams and therefore instructs fourdifferent uplink beams to be transmitted. In this case, the terminal maytransmit the RS for the measurement of four uplink beams by differentCP-OFDM symbols or DFT-S-OFDM symbols (i.e., transmission through the RSfor the measurement of four uplink beams). As another example, ifdifferent beams are frequency-divided (frequency division multiplexing(FDM)) in the same CP-OFDM (or DFT-S-OFDM) symbol and can betransmitted, less than four CP-OFDM (or DFT-S-OFDM) symbols may be usedto transmit the RS for the measurement of the uplink beam.

The base station may transmit information on how many uplink beams areto be transmitted to the terminal through UE-specific RRC, MAC CE, groupcommon DCI, or UE-specific DCI. For example, if the base stationinstructs the transmission of N uplink beams, the terminal transmits theN uplink beams. The base station receiving the uplink beams from theterminal may determine the downlink beam (since beam mutuality existsbetween the uplink beam-pair and the downlink beam-pair).

The base station may inform the terminal of the information on thedownlink beam through the MAC control element (CE), the UE-specific DCI,or the group common DCI. At this time, information on one or two or morebeam IDs (or resource indexes on which beams are transmitted) may beincluded. The base station informing the information may transmit thedownlink data and the control information, which are transmitted to thecorresponding terminal, through the informed beam. At this time, apreviously promised rule is required between the base station and theterminal. For example, the base station may transmit the downlink dataand the control information, which are transmitted just after informingthe terminal of the downlink beam, through the informed beam.

As another example, the base station-terminal may apply the informedbeam based on a timer. That is, the base station drives the timer afterinforming the terminal of the downlink beam, and the terminal drives thetimer after receiving the downlink beam information from the basestation. Before the timer expires, the terminal may form a beam in thedirection of the beam that the base station informs or may switch thebeam in the direction of the beam that the base station informs toprepare for receiving the downlink. Such a timer-based operation uses alarge subcarrier spacing, so that the problem in that the base stationand the terminal may quickly form or change the beam in a mmWave systemin which a symbol length is short and a length of the subframe (or slot)is short can be solved.

The base station determining the uplink beam may inform the terminal ofthe information on the uplink beam through the MAC control element (CE),the UE-specific DCI, or the group common DCI. At this time, theinformation on which beam the uplink transmission may be performedthrough may be included (i.e., ID information of a beam (or index of theresource to which the beam is transmitted) may be included). At thistime, if one beam ID is included, the terminal performs the uplinktransmission to the corresponding beam. If at least two beam IDs areincluded, the terminal performs the uplink transmission to thecorresponding beams. For the operation, a previously promised rule isrequired between the base station and the terminal. For example, theterminal may transmit the uplink data and the control information, whichare transmitted just after receiving the information on the uplink beamfrom the base station, through the corresponding beam (or correspondingbeams).

As another example, the base station-terminal may apply the beam basedon the timer. That is, the base station drives the timer aftertransmitting the uplink beam information to the terminal, and theterminal drives the timer after receiving the uplink beam informationfrom the base station. The terminal may switch in the direction of thebeam (or beams) that the base station instructs before the timer expiresto prepare for the uplink transmission. Such a timer-based operationuses a large subcarrier spacing, so that the problem in that the basestation and the terminal may quickly form or change the beam in a mmWavesystem in which a symbol length is short and a length of the subframe(or slot) is short can be solved.

FIGS. 7 and 8 illustrate an example of an operation of newly introducinga PHR triggering event when a serving beam is changed and reducing adelay at the time of transmitting the corresponding PHR.

FIGS. 7 and 8 illustrate an example in which a UL grant for a PHRtransmission is previously included in a beam switch procedure when abeam is changed and an example of performing whether to determine thePHR triggering at the time of the operation of the beam switch timer.

FIG. 7 illustrates an example of an operation of newly introducing a PHRtriggering event at the time of changing a serving beam for thetransmission of the power headroom information is changed and reducing adelay when the corresponding PHR is transmitted. In FIG. 7, an exampleof uplink beam management in case of Intra-TRxP beam change (that is,case of changing the source beam and the target beam within the sameTRP) is shown.

The terminal may perform the beam measurement report according to thebeam measurement setting and the measurement event trigger (S710). Whenthe beam needs to be changed according to the beam measurement report,the base station may transmit the beam change command message to theterminal (S720) and may include the information on the target beam andthe UL grant for the PHR transmission in the message.

Therefore, the terminal and the base station may change the beam (S730),and when the PHR is triggered, the terminal and the base station mayreport the PHR using the UL grant (S740). As described above, theterminal may reduce the transmission delay using the received UL grantwithout transmitting the separate SR to transmit the PHR. The contentsof the PHR event trigger conditions and the method for reporting PHR arethe same as described, which will be omitted hereinafter.

FIG. 8 illustrates an example of an operation of newly introducing a PHRtriggering event when the beam for the transmission of the powerheadroom information is changed and reducing a delay when thecorresponding PHR is transmitted. FIG. 8 illustrates an example of theuplink beam management in the case of changing the Inter-TRxP beam (thatis, case of changing from the source beam to the target beam of anotherTRP).

Unlike the Intra-TRxP beam change, in the case of the Inter-TRxP beamchange, an operation of including information (inter-TRxP beam switchindicator) indicating whether to change an inter-TRxP beam on a beamswitch command that the base station transmits to the terminal andtransmitting the information is provided. At this time, in the case ofthe Intra-TRxP beam change, an operation of transmitting by settingInter-TRxP beam switch indicator=0, and in case of the Inter-TRxP beamchange, an operation of transmitting by setting Inter-TRxP beam switchindicator=1 may be provided. Alternatively, only the case of changingthe inter-TRxP beam, the indicator may also be provided.

The reason of including the inter-TRxP beam switch indicator is tocorrect the PH according to the TRP change. That is, if the TRPs of thesource beam and the target beam are different, the base station correctsthe PH determined based on the source beam to be suited for the targetbeam or the terminal may perform the correction. However, even when theinformation is not included, the base station may determine whether tochange the beam between the target TRPs to correct the PH.

In addition, steps S810 to 840 are the same as steps S710 to S740, whichwill be omitted hereinafter.

FIGS. 9 to 12 illustrate an example of an operation of newly introducinga PHR triggering event when a serving beam is changed and reducing adelay at the time of transmitting the corresponding PHR, and illustratean example of an operation of previously performing whether to determinePHR triggering when a beam is changed, including and transmitting a ULgrant for a PHR transmission in a beam switch procedure, andtransmitting a PHR after a beam switch timer.

FIG. 9 illustrates an example of an operation of transmitting powerheadroom information when a beam switch operation is performed.

FIG. 9 illustrates an example of an operation of transmitting theexisting beam switch message when the PHR event is not triggered.

The PHR-related information may not be included in the control messagetransmitted/received at the beam switch operation or may be included asNULL.

In detail, the terminal may perform the beam measurement reportaccording to the beam measurement setting and the measurement eventtrigger (S910). When the beam needs to be changed according to the beammeasurement report, the base station may transmit the beam changecommand message to the terminal (S920) and the terminal and the basestation may change the beam. Further, the terminal may a beam changecomplete message to the base station (S930).

At this time, if the PHR event is not triggered, the PHR relatedinformation may not be included in the beam measurement report, the beamchange command, and the beam change complete message and may be includedas the NULL.

FIG. 10 illustrates an example of an operation for transmitting thepower headroom information in the beam switch operation.

In FIG. 10, when a PHR event between Intra-TRxPs is triggered, anoperation of adding PH related information to the existing beam switchmessage and transmitting the same will be described by way of example.That is, since the source beam and the target beam is the same basestation (DU), an operation of performing a PHR during the beam switchoperation to reduce a PH transmission delay is performed.

A detailed example of the operation includes an operation in which (1)when the terminal performs beam measurement report by the serving beam(S1010), (2) the terminal transmits PHR SR along with the beammeasurement report based on the PHR trigger condition (S1020), (3) abase station (source beam) transmits a UL grant to a terminal at thetime of the beam switch command (CMD) transmission (S1030), (4) theterminal transmits a PHR when the terminal transmits a beam switchconfirm request by the target beam (S1040).

FIG. 11 illustrates an example of an operation for transmitting thepower headroom information in the beam switch operation.

FIG. 11 illustrates an example of an operation of adding andtransmitting the PH related information to the existing beam switchmessage when the terminal triggers the Inter-TRxP PHR event.

At the time of generating the inter-TRP beam switch, Case 1) when theterminal determines whether the inter-TRP is changed (when the basestation previously informs the terminal of the beam group information ofthe TRxP, for example, when the base station broadcasts the systeminformation or informs the corresponding terminal of the beam groupinformation of the TRxP through the RRC (re)configuration), the Pathlossis changed, and therefore the terminal defines the generation of thebeam switch as new PHR triggering.

Therefore, the terminal triggers the PHR event and reports the triggeredPHR event to the base station.

A detailed example of the operation is an operation in which (1) whenthe terminal performs beam measurement report by the serving beam(S1110), (2) the terminal transmits PHR SR along with the beammeasurement report based on the PHR trigger condition (S110), (3) a basestation (source beam) transmits a UL grant to a terminal at the time ofthe beam switch CMD transmission (S1120) (4) the terminal transmits aPHR when the terminal transmits a beam switch confirm request by thetarget beam (S1130).

FIG. 12 illustrates an example of an operation for transmitting thepower headroom information in the beam switch operation.

In FIG. 12, when the base station triggers the inter-TRxP PHR event, anoperation of adding PH related information to the existing beam switchmessage and transmitting the same is provided.

A detailed example of the operation includes an operation in which (1)when the terminal performs beam measurement report by the serving beam(S1210), (2) the terminal transmits PHR SR along with the beammeasurement report based on the PHR trigger condition (S1210), (3) abase station (source beam) transmits a UL grant to a terminal at thetime of the beam switch CMD transmission (S1220), (4) the terminaltransmits a PHR when the terminal transmits a beam switch confirm by thetarget beam (S1230).

FIG. 13 illustrates an example of transmitting UL data through aplurality of uplink beam-pairs. In FIG. 13, an embodiment of the case inwhich the plurality of beams of the base station that are the uplinkreception beams exist within the same TRxP (1310) will be described.

There may be the situation of the network or the base station whichsupports a function of simultaneously operating the plurality of servingbeams to perform the uplink transmission, the case in which the beam ofthe base station, which is the uplink reception beam, exists within thesame TRxP between the current serving beam and the target beam, but inparticular, in the case in which the current serving beam and the targetbeam of the base station, which are the UL reception beam, existseparately in another TRxP (FIG. 14), since the location of the terminalis the same, but the TRxPs, which are points at which the base station(DU) actually transmits and receives the source beam and the targetbeam, are different, the PHR report that the terminal transmits mayinclude the PH information based on the downlink transmission beam-pairand a plurality of PH information based on the uplink transmissionbeam-pair.

FIG. 14 illustrates an example of transmitting UL data through aplurality of uplink beam-pairs. In FIG. 14, an embodiment of the case inwhich the plurality of beams of the base station that are the uplinkreception beams, separately exist within another TRxP (1410) will bedescribed.

Even in the network or the base station which supports the function ofperforming the uplink transmission by simultaneously operating theplurality of serving beam, in particular, when the current serving beamand the target beam of the base station, which is the uplink receptionbeam, separately exist in another TRxP, since the location of theterminal is the same but the TRxPs, which are a point where the basestation (DU) actually transmits and receives the source beam and thetarget beam, are different, the physical locations are different andthus the PH information of the corresponding source beam-pair and targetbeam-pair are highly likely to be different, the plurality of PHinformation is required.

FIG. 15 illustrates an example of transmitting UL data when the downlinkand uplink beam-pairs are different. FIG. 15 illustrates an embodimentof the case in which the base station beam that is the downlinktransmission beam and the base station beam that is the uplink receptionbeam exist within the same TRxP (1510).

The terminal does not know the reception beam (base station receptionbeam) information of the base station upon the uplink transmission inthe case in which the base station dynamically changes the uplinkreception beam, the terminal may calculate PH for a plurality ofcandidate beams and transmit the calculated PH.

FIG. 16 illustrates an example of transmitting UL data when the downlinkand uplink beam-pairs are different. FIG. 16 illustrates an embodimentof the case in which the base station beam that is the downlinktransmission beam and the base station beam that is the uplink receptionbeam, separately exist within another TRxP (1610).

When the downlink transmission beam-pair and the uplink transmissionbeam-pair are different, the case in which the current serving beam andthe target beam exist within the same TRxP, but in particular, when thecurrent serving beam and the target beam separately exist within anotherTRxP, the location of the terminal is the same, but the TRxPs, which arepoints at which the base station (DU) actually transmits and receivesthe source beam and the target beam are different. Therefore, theinformation on a PH based on a downlink transmission beam-pair andinformation on a plurality of PHs based on uplink transmission beam-pairto a PHR report that a terminal transmits may be provided.

Alternatively, when the base station informs the terminal of thereception beam (base station reception beam) information in advance uponthe transmission of the uplink, the terminal may transmit a single PHcorresponding to a corresponding uplink transmission beam-pair isprovided; and

Alternatively, when the terminal does not know the reception beam (basestation reception beam) information upon the uplink transmission, amethod for calculating PHs for a plurality of candidate beams andtransmitting the calculated PHs is provided.

FIG. 17 illustrates an example of an operation of performing an uplinkresource allocation by transmitting, by the terminal, information on SR,BSR, and PHR to the base station and receiving an UL grant from the basestation, in the LTE for the uplink resource allocation, and an exampleof a required time delay.

The delay may occur in a case in which the base station performs uplinkscheduling dynamically or a case where a fast uplink transmission may beperformed since a supported service requires low latency performance.

That is, after the terminal transmits the BSR (1710), the base stationtransmits the UL grant (1720) for the resource allocation of the uplinktransmission and then performs the uplink data transmission (1730). Atthis time, the terminal may know the UL reception beam information ofthe base station upon the transmission of the PH to transmit the singlePH. If a single PH is transmitted based only on the UL reception beaminformation of the corresponding base station, there is a problem inthat the base station cannot update the UL reception beam having abetter beam gain because the channel environment is changed or the ULreception beam even when the corresponding beam gain is changed.

FIG. 18 illustrates an example of an operation of configuring a PHRtriggering event related to a beam width change for the transmission ofthe power headroom information considering beamforming.

An example of an operation in the case in which different beam widthsper synchronization signals (PSS, SSS), a control channel (control), anda data transmission channel in a network supporting beamformingtransmission are used will be described. For example, the example of thecase in which the synchronization signal uses a very wide beam, thecontrol channel uses a wide beam, and the data channel uses a narrowbeam will be described.

The terminal may understand the synchronization signals (PSS and SSS)and the beamforming transmission beam width of the control channel(control) and the data transmission channel. The terminal may identifythe beamforming transmission beam width of the synchronization signals(PSS, SSS), the control channel (control), and the data transmissionchannel through the negotiation (SI and UE capability or RRC(re)configuration) between the terminal and the base station (S1810,S1820, S1830). The terminal may identify a PHR parameter set as thefollowing Table 4 as an example based on the SI received from the basestation, UE capability or RRC (re)configuration.

TABLE 4 Beam Beam width Periodic_timer ProhibitPHR_timer changedl-PathlossChange Omnidirectional ◯ Normal X ◯ (1) Very wide beam ◯Shorter ◯ ◯◯ (29) Wide beam (58) ◯ Very shorter More ◯◯◯ frequently ◯narrow beam (112) ◯ Approximately zero Very ◯◯◯◯ frequently ◯

In Table 4, Applicable: O, Non-applicable: X

The operation of the above Table 4 indicates an operation of applyingPeriodic timer, and setting ProhibitPHR_timer to be zero or a very smallvalue and setting dl-PathlossChange value to be a large value since thebeam change is frequently generated, for example, when the data channeluses a narrow beam “(when transmission beam is narrow as 360/112).”

FIG. 19 illustrates an example of the MAC CE format for the transmissionof the power headroom information considering beamforming.

FIG. 19 illustrates an example of applying PH per beam. An example ofapplying PH per beam is a method for transmitting additional information(1910, 1920, 1930) on beam in addition to the existing 6-bit PH value.At this time, the information on the beam may be configured as anexplicit beam index and may be configured implicitly.

FIG. 20 illustrates another example of the MAC CE format for thetransmission of the power headroom information considering beamforming.FIG. 20 illustrates an example of applying PH per TRxP.

Referring to FIG. 20, indexes 2010, 2020, and 2030 of TRxP may beadditionally included in the MAC CE. At this time, the information onthe TRxP may be configured as an explicit beam index or may beconfigured implicitly.

Meanwhile, in the conventional LTE system, a dual connectivity based PHRtriggering event is defined. When at least one path-loss is changedabove a threshold value in the case in which one terminal transmits anuplink data for a macro cell (MeNB) and an uplink for a small cell(SeNB) on a plurality of transmission links, a method for calculating,by a terminal, PH values for both of the uplink for the macro cell(MeNB) and the uplink for the small cell (SeNB) and transmitting thecalculated PH values to the uplink for the macro cell (MeNB) and theuplink for the small cell (SeNB), respectively, is provided.

The present disclosure includes a method for performing an operation oftriggering PHR and transmitting a PHR as an operation including thefollowing option based on whether the uplink transmission of theterminal that performing beamforming is operated in a high frequencyband (HF Higher Frequency).

When an RF circuit and a power amplifier operate independently toseparately operate each maximum UL transmission power (Pc_max_MeNB,Pc_max_SeNB) on two uplinks, the base station may transmit thecorresponding information to a terminal as system information (SI) andRRC (re)configuration. The terminal selects one of an option of (1)transmitting all PHRs when at least one of two uplink path-losses ischanged above a threshold value or an option of (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from the pre-configured PHR events based on thetransmitted system information (SI) and RRC (re)configuration and maytrigger and transmit the PHR.

Alternatively, the base station may select one of PHR trigger eventoptions of (1) transmitting all PHRs when at least one of two uplinkpath-losses is changed above a threshold value or (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from PHR events and configure the information in theterminal as system information (SI) and RRC (re)configuration isprovided.

(1) In case of legacy DC LF+LF (low frequency: sub 6 GHz).

When at least one path-loss is changed above a threshold value in thecase in which one terminal performs an uplink transmission for a macrocell (MeNB) and an uplink for a small cell (SeNB) on a plurality oftransmission links, the terminal may calculate PH values for both of anuplink for a macro cell (MeNB) and an uplink for a small cell (SeNB) andtransmit the calculated PH values to the uplink for the macro cell(MeNB) and the uplink for the small cell (SeNB), respectively, isprovided.

(2) In case of EN-DC (LTE-NR DC) LF+HF (high frequency: i.e., 28 GHz).

(2-1) Application of independent PHR event: The PHR event of the HF isnot reported to an LF base station.

When one terminal transmits performs an uplink transmission for a macrocell (MeNB) and an uplink for a small cell (SeNB) on a plurality oftransmission links, a case in which one frequency band of two uplinks isincluded in a low frequency sub 6 GHz and the remaining uplink isincluded in a high frequency: i.e., 28 GHz is assumed.

When each of the maximum UL transmission power (Pc_max_meNB,Pc_max_seNB) is separated and operated on two uplinks by operating theRF circuit and the power amplifier independently, even when thepath-loss of each link is changed more than the threshold value, theterminal may transmit a PHR only to the corresponding link.

In this case, the base station assumes the case in which one frequencyband of two uplinks is included in a low frequency sub 6 GHz and theremaining uplink is included in a high frequency: i.e., 28 GHz.

When an RF circuit and a power amplifier operate independently toseparately operate each maximum UL transmission power (Pc_max_MeNB,Pc_max_SeNB) on two uplinks, the base station may transmit thecorresponding information to a terminal as system information (SI) andRRC (re)configuration. The terminal may select one of an option of (1)transmitting all PHRs when at least one of two uplink path-losses ischanged above a threshold value or an option of (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from PHR events that the base station previouslyconfigures based on the transmitted system information (SI) and RRC(re)configuration and may trigger and transmit the selected PHR.

Alternatively, the base station may select one of PHR trigger eventoptions of (1) transmitting all PHRs when at least one of two uplinkpath-losses is changed above a threshold value or (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from PHR events and configure the information in theterminal as system information (SI) and RRC (re)configuration.

(2-2) When at least one path-loss is changed above a threshold value inthe case in which one terminal performs an uplink transmission for amacro cell (MeNB) and an uplink for a small cell (SeNB) on a pluralityof transmission links, the terminal may calculate PH values for both ofan uplink for a macro cell (MeNB) and an uplink for a small cell (SeNB)and transmit the calculated PH values to the uplink for the macro cell(MeNB) and the uplink for the small cell (SeNB), respectively.

(3) In case of NR STA: HF+HF.

(3-1) When at least one path-loss is changed above a threshold value inthe case in which one terminal may perform an uplink transmission for amacro cell (MeNB) and an uplink for a small cell (SeNB) on a pluralityof transmission links, the terminal may calculate PH values for both ofan uplink for a macro cell (MeNB) and an uplink for a small cell (SeNB)and transmit the calculated PH values to the uplink for the macro cell(MeNB) and the uplink for the small cell (SeNB), respectively.

(3-2) Application of independent PHR event: The PHR event of the HF isnot reported to an LF base station.

When one terminal performs an uplink transmission for a macro cell(MeNB) and an uplink for a small cell (SeNB) on a plurality oftransmission links, it is assumed that one frequency band of two uplinksis included in a low frequency sub 6 GHz and the remaining uplink isincluded in a high frequency: i.e., 28 GHz.

When each of the maximum UL transmission power (Pc_max_meNB,Pc_max_seNB) is separated and operated on two uplinks by operating theRF circuit and the power amplifier independently, even when thepath-loss of each link is changed more than the threshold value, theterminal may transmit a PHR only to the corresponding link is provided.

In this case, it is assumed that one frequency band of two uplinks isincluded in a low frequency sub 6 GHz and the remaining uplink isincluded in a high frequency: i.e., 28 GHz.

When an RF circuit and a power amplifier operate independently toseparately operate each maximum UL transmission power (Pc_max_MeNB,Pc_max_SeNB) on two uplinks, the base station may transmit thecorresponding information to a terminal as system information (SI) andRRC (re)configuration. The terminal selects one of an option of (1)transmitting all PHRs when at least one of two uplink path-losses ischanged above a threshold value or an option of (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from the pre-configured PHR events based on thetransmitted system information (SI) and RRC (re)configuration and maytrigger and transmit the PHR.

Alternatively, the base station may select one of PHR trigger eventoptions of (1) transmitting all PHRs when at least one of two uplinkpath-losses is changed above a threshold value or (2) transmitting allPHRs when at least one of two uplink path-losses is changed above athreshold value from PHR events and configure the information in theterminal as system information (SI) and RRC (re)configuration.

Meanwhile, in the conventional LTE system, discrete Fouriertransform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM)is used as an uplink waveform. In contrast, in the 5G communicationsystem, both the DFT-S-OFDM and cyclic prefix-orthogonal frequencydivision multiplexing (CP-OFDM) can be used as a waveform in order tomaximize the flexibility of the system operation. Since differentwaveforms have different characteristics, it is necessary to constructpower headroom information considering this point.

For example, the DFT-S-OFDM has a lower peak-to-average power ratio(PAPR) than that of the CP-OFDM. Therefore, in order to support the highPAPR of the CP-OFDM, a power amplifier (PA) having a wide linear regionis required, which can increase the price of the terminal. Therefore, inorder to support different waveforms using the same PA in the sameterminal, back-off of the transmission power may be performed in orderto reduce the amount of signals out of a linear region of PA due to highPAPR when the CP-OFDM may be used. In this case, the fact that theterminal performs the back-off using the CP-OFDM may be included in thepower headroom information. More specifically, bit informing whether ornot the terminal performs back-off may be included in the correspondingpower headroom information. If the back-off is performed, the bit may beset to be “1.” Also, if the terminal has performed the back-off of thetransmission power due to the use of the CP-OFDM, the P_(CMAX) specifiedin the above Equations 3a, 3b, and 3c may be changed to P _(CMAX). Atthis time, P _(CMAX)=P_(CMAX)−Δ and Δ is a back-off value that theterminal performs.

FIG. 23 illustrates an example of a change operation of the DFT-S-OFDMor the CP-OFDM which is a UL waveform. More specifically, a controlsignaling operation for a dynamic uplink waveform change indication isprovided.

Unlike the conventional LTE using only the DFT-S-OFDM for the uplink(UL) transmission, the (5G) NR is operated using both of the DFT-S-OFDMand the CP-OFDM. Each UL waveform has advantages and disadvantages asfollows. The CP-OFDM exhibits improved hash spectrum efficiencyperformance, and the DFT-S-OFDM exhibits lower PAPR performance and thusrequires a relatively small power back-off value.

Therefore, there is a need to change the DFT-S-OFDM or the CP-OFDM,which is the UL waveform, by a sudden signal drop or the like whichoccurs due to required reliability (link budget) and a blockage duringthe beamforming transmission process for a coverage extension of a cell.

More specifically, it is advantageous to select the DFT-S-OFDM for thecoverage extension of the cell. When the required reliability (linkbudget) level is high, for example, it is advantageous to selectDFT-S-OFDM in a situation of supporting traffic which is a service typesuch as URLLC. Also, it is advantageous to select DFT-S-OFDM when thesudden signal drop or the like which occurs due to the blockage occursduring the beamforming transmission process. On the other hand, it isadvantageous to select the CP-OFDM in a relatively close cell region(terminal location or cell size).

It is an example of the change operation of the DFT-S-OFDM or theCP-OFDM which is a UL waveform. More specifically, the control signalingoperation for a dynamic uplink waveform change indication is provided.

FIG. 21 shows a method for a dynamic uplink waveform change indicationin the PHY layer for a control signaling operation for the dynamicuplink waveform change indication in the first embodiment.

FIG. 21A illustrates a method for determining, by a base station, anuplink waveform and transmitting, by a terminal, information on adynamic uplink waveform change to a DCI transmitted on a PDCCH.

FIG. 21B illustrates a method of transmitting information on a dynamicuplink waveform change to a UCI transmitted on a PUCCH as a method inwhich the terminal feeds back the uplink waveform to the base station.

As an example of such an operation, as a method of adding a fieldexplicitly indicating an uplink waveform to DCI, the base station maytransmit information on an uplink waveform as a new field includingUL_waveform_indicator 2120 and 2120 to a terminal through an informationbit within DCI or other information bit within the PDCCH. t this time,for example, the base station may describe DFT-S-OFDM by “1” and CP-OFDMby “0” or DFT-S-OFDM by “0” and CP-OFDM by “1.”

In addition to the above method of explicitly expressing the uplinkwaveform, as a method of indicating the UL waveform change, the basestation may transmit information on an uplink waveform as a new fieldincluding UL_waveform_change_indicator 2111 and 2121 to the terminalthrough an information bit within DCI or other information bit withinthe PDCCH.

In this case, the base station may set the correspondingUL_waveform_change_indicator to be 0 when the same uplink waveform asthe previously transmitted uplink waveform is used, and set thecorresponding UL_waveform_change_indicator to be 1 when the uplinkwaveform is changed. Alternatively, on the contrary, the base stationmay set UL_waveform_change_indicator to be 1 when the same uplinkwaveform as the uplink waveform previously transmitted is used and setUL_waveform_change_indicator to be 1 when the uplink waveform ischanged.

As described above, the base station may directly indicate the use ofthe DFT-S-OFDM or CP-OFDM through UL_waveform_indicator as a new fieldin the PDCCH at the PHY layer or inform the uplink waveform of newtransmission compared with the previous transmission is changed.

Alternatively, there is an operation method using a DCI fallback 2112and 2122 existing in the existing LTE. For example, if the previousuplink waveform is changed to indicate a new uplink waveform, the basestation may indicate a change from DFT-S-OFDM to CP-OFDM or a changefrom CP-OFDM to DFT-S-OFDM using a DCI fallback.

Here, the uplink waveform, which is described as the previous uplinkwaveform, may be extended as follows: an operation based on an initialuplink (UL) waveform of the CP-OFDM or the DFT-S-OFDM set to be used forthe uplink transmission of the RACH message3 (MSG3) to be used in aninitial access.

In one example, an operation based on a reference uplink waveform isindicated to be determined as an uplink waveform, which is referenced,among two uplink waveforms, CP-OFDM, or DFT-S-OFDM after an initialtransmission.

In one example, an operation indicates whether to change an uplinkwaveform based on an uplink waveform of a previous transmission asanother embodiment.

In one example, a method for indicating, by a base station, whether tochange an uplink waveform to a terminal through a DCI fallback, forexample, at the time of changing from DFT-S-OFDM to CP-OFDM based on aninitial uplink (UL) waveform reference, a reference uplink waveformreference, and an uplink waveform reference of a previous transmissionas illustrated above or at the time of changing from additionally fixeduplink waveform CP-OFDM or DFT-S-OFDM to another uplink waveform.

A method for illustrating a method for indicating, by a base station, anuplink waveform change to a terminal through a DCI fallback at the timeof changing from CP-OFDM, which is a fixed uplink waveform, toDFT-S-OFDM. The methods may be extended to the method for indicating, bya base station, an uplink waveform change to a terminal through a DCIfallback or the method of directly instructing a use of DFT-S-OFDM orCP-OFDM through UL_waveform_indicator; or the method for informingwhether to change an uplink waveform of a new transmission with respectto the previous transmission through UL_waveform_change_indicator.

The method for a dynamic uplink waveform change indication in a PHYlayer for a control signaling operation for a dynamic uplink waveformchange indication can be extended to the method for an operation methodbased on a PDCCH and a DCI at a PHY layer when a base station transmitscorresponding information to the terminal and the operation based on thePUCCH and the UCI when the terminal feeds back the uplink waveformrelated information to the base station. The method for a dynamic ULwaveform change indication in a PHY layer can perform the uplinkwaveform change operation in a short time such as transmission timeInterval (TTI) (about 1 msec in the LTE and about ⅛ in the NR (5G)), buthas a disadvantage in that resources in the PDCCH and DCI (or PUCCH andUCI), which are relatively scarce resources, are fixedly consumed and itis impossible to support adaptive modulation and coding (AMC) and H-ARQin the case of the PDCCH and the DCI (or PUCCH and UCI).

FIGS. 22A and 22B illustrate a new downlink MAC CE (Control Element) forUL_waveform_indicator or UL_waveform_change_indicator transmission as anindication method in a MAC layer for a control signaling operation for adynamic uplink waveform change indication according to a secondembodiment.

FIG. 22A shows a method in which a base station determines an uplinkwaveform and instructs a terminal through a downlink MAC CE.

In FIG. 22, it is possible to transmit to the terminal whether theuplink waveform or the uplink waveform is changed in MACE through a newfield UL_waveform_indicator 2210 or UL_waveform_change_indicator 2211.

In addition, FIG. 22B illustrates a method for transmittingUL_waveform_indicator 2220 or UL_waveform_change_indicator 2221 using 2bits reserved in one PHR of the existing uplink MAC CE.

However, the transmission method through the MAC CE causes a delay ofabout 10 transmission time intervals (TTI) according to the transmissionon the PDSCH (DL MAC CE) or the PUSCH (UL MAC, i.e., PHR) since thetransmission is made on the data channel. In addition, the transmissionmethod through the MAC CE has an advantage in that the transmission ismade on the data channel and the support of the adaptive modulation andcoding (AMC) and the H-ARQ can be made, the robust transmission is made.

FIG. 23A illustrates a method for indicating, by a base station, adynamic uplink waveform change to a terminal based on an RRC message asan indication method in an RRC layer for a control signaling operationfor a dynamic uplink waveform change indication according to anembodiment of the present disclosure.

That is, the base station may transmit an uplink waveform or whether anuplink waveform is changed to an RRC configuration message or an RRCreconfiguration message by using UL_waveform_indicator 2310 orUL_waveform_change_indicator 2320 upon initial access.

The method has an advantage in that resources are not fixedly consumedon the PDCCH and the DCI (or PUCCH and UCI) which are scarce resourcesand for example, the MAC CE index or a reserved bit of the PHR of theexisting MAC CE is not used in a communication standard for a new MACCE. However, a time scale of RRC signaling can be applied to the case inwhich the uplink waveform configuration is slowly changed due to a delayof about 100 TTI. For example, when a control operation is performedwith an RRC message due to a cell change (scell, PScell addition,handover and RRC state transition), a method for indicating, by a basestation, an uplink waveform to a terminal by newly definingUL_waveform_indicator or UL_waveform_change_indicator as an RRCconfiguration message or a RRC reconfiguration message is provided.

FIG. 23B illustrates a method for feeding back, by a terminal, an uplinkwaveform indicator using an RRC message according to an embodiment ofthe present disclosure.

As shown in FIG. 23B, the terminal also includes an operation of feedingback the corresponding uplink waveform indicator (UL waveform indicatoror UL_waveform_change_indicator) 2320 and 2321 to an RRC connectionrequest message, an RRC configuration request message, or a reconfiguredRRC reconfiguration request message.

As illustrated in FIG. 24, a fourth embodiment includes a method forindicating, by a base station, UL_waveform_indicator information to aterminal to carry the UL_waveform_indicator information indicating anuplink waveform on fields such as MIB, SIB1, and SIB2 of systeminformation as a method for indicating an uplink waveform through systeminformation (SI) for a control signaling operation for indicating adynamic uplink waveform change according to an embodiment of the presentdisclosure.

The base station may indicate an uplink waveform by system information(S2410), which relates to an initial UL waveform indication method, andspecifically, is suitable to set an UL waveform for an RACH MSG3transmission. Since a terminal (RRC INACTIVE or RRC IDLE) that is notconnected to a base station powers off an RF module and a receivingmodule for most of the time for a low power operation, the UE in the RRCIDLE state receives the system information prior to receiving pagingduring on duration in which CN-based paging (paging transmitted from theMME) is received or the UE in the RRC INACTIVE state receives the systeminformation prior to receiving paging during on duration in whichRAN-based paging (paging transmitted from anchor gNB) is received,thereby configuring the related information for the reception of thepaging or performing the configuration required upon the initial accessand the resource information (e.g., RACH resource and transmission modeconfiguration).

However, since the system information is always transmitted by thesystem and received by all the terminals within the base station cell,the transmission of the uplink waveform with a large number ofinformation bits increases the control burden. Therefore, the basestation may indicate that the CP-OFDM or DFT-S-OFDM is used as theuplink waveform by a minimum number of bits, for example, 1 bit. Sincethe terminal (RRC INACTIVE or RRC IDLE) not connected to the basestation does not receive the system information frequently and moves tothe corresponding base station in case of a mobile terminal and isoperated based on the first received system information, the method forindicating an uplink waveform by system information (SI) directly(explicitly) indicates OFDM or DFT-S-OFDM as an uplink waveform throughUL_waveform_indicator 2420. The method of indicating a change from arelative previous uplink waveform by UL_waveform_change_indicator is notsuitable for the terminal which—does not receive the continuousreception.

In case of the terminal (RRC INACTIVE or RRC IDLE) not connected to thebase station or a mobile terminal, since the terminal which moves to thecorresponding base station and initially accesses the corresponding basestation performs initial transmission with limited RACH resources andinformation, as the method for indicating an uplink waveform by thesystem information (SI), the method for indicating a waveform to be usedfor an uplink transmission of an RACH MSG3 which is the initial accessis mainly used.

The present embodiment includes both of the method for transmittinginformation on an uplink waveform using MSB, SIB1, SIB2, or then SIBxand minimum SI and a method for transmitting and indicating informationon the uplink waveform to remaining minimum system information (RMSI) orother SI or on-demand other SI according to a terminal request. Inaddition, the method for using system information may be used toindicate a reference uplink waveform which is a reference of an uplinkwaveform in the next RRC connected state and a dynamic uplink waveformindication immediately applied to the uplink transmission as well as themethod for indicating a waveform to be used for an uplink transmissionof RACH MSG3 which is the system information initial access.

FIG. 25 illustrates an operation of calculating, by a terminal, a PHRand reporting the calculated PHR and performing, by a base station, ULscheduling with corresponding information.

The base station and the terminal performs the uplink transmission basedon the PHY layer indication method (PDCCH/DCI, or PUCCH/UCI) for thecontrol signaling operation for the dynamic uplink waveform changeindication, the indication method by a MAC CE in the MAC layer, theindication method by an RRC message in an RRC layer, and the indicationmethod by the system information.

In particular, there is a need to determine a P_max value which is areference when the terminal calculates the PH to transmit the PHR in thePHR report for the uplink power control. By the way, the value ischanged according to the uplink waveform. The DFT-S-OFDM has a lowerpeak-to-average power ratio (PAPR) than that of the CP-OFDM. Therefore,the DFT-S-OFDM has a larger P_max value which can be output, comparedwith the CP-OFDM. That is, in order to support the high PAPR of theCP-OFDM, a power amplifier (PA) having a wide linear region is required,which can increase the price of the terminal. Therefore, in order tosupport different waveforms using the same PA in the same terminal,back-off of the transmission power may be performed in order to reducethe amount of signals out of a linear region of PA due to high PAPR whenthe CP-OFDM may be used.

In this case, by the explicit method, the fact that the terminalperforms the back-off using the CP-OFDM may be included in the powerheadroom information. More specifically, a bit P notifying whether ornot the terminal performs back-off is defined in the power headroominformation. If the back-off is performed, P may be set to be “1.” Also,if the terminal has performed the back-off of the transmission power dueto the use of the CP-OFDM, the P_(CMAX) specified in the above Equations3a, 3b, and 3c may be changed to P _(CMAX). At this time, P_(CMAX)=P_(CMAX)−Δ and Δ is a back-off value that the terminal performs.

In addition to the explicit method as described above, the presentembodiment relates to the reference uplink waveform indication method,and the method for transmitting a reference waveform indication todetermine a P_max value which is a reference when the terminalcalculates the PH to transmit the PHR.

Since the base station determines the uplink waveform, the base stationcan know the uplink waveform at the time of the uplink scheduling, butthe terminal cannot know the accurate uplink waveform informationbecause of previously feeding back the PHR information.

Therefore, according to the present embodiment, first, a method forexplicitly indicating, by a terminal, a reference uplink waveform(DFT-S-OFDM or CP-OFDM) at the time of a PHR transmission (S2510) and amethod for figuring out, by a base station receiving the referenceuplink waveform, corresponding uplink waveform indication informationand applying a P_max correction value when being different from anactual uplink waveform (S2520) to perform uplink scheduling (determininguplink resource allocation and the number of allocated sub carriers)(S2530) are provided.

Second, a method for explicitly indicating, by a terminal, a referenceuplink waveform (DFT-S-OFDM or CP-OFDM) at the time of the PHRtransmission (S2510) and a method for limiting, by a base stationreceiving the reference uplink waveform, a corresponding uplink waveformto perform the uplink scheduling (determining uplink resource allocationand the number of allocated sub carriers) (S2530) are provided.

Third, the base station and the terminal define the P_max value based onthe pre-defined reference uplink waveform and calculate the PH based onthe defined P_max value to transmit the PHR. The base station receivingthe same may include a method for setting the P_max correction value tobe 0 if the reference uplink waveform and the reference uplink waveformto be actually used are the same, and being operated by applying theP_max correction value which is the predefined or implemented value ifthe reference uplink waveform and the reference uplink waveform to beactually used are different.

FIG. 28 illustrates an operation of that the base station determineswhether the uplink waveform which is a reference in the PHR transmittedby the terminal and the waveform to be applied to the actual uplinktransmission are the same (S2610), and corrects the PH reception valueand P_max if it is determined that the uplink waveform included in thePHR and the waveform to be applied to the actual uplink transmission aredifferent (S2640) to allocate and schedule the uplink resource.

Further, the base station identifies whether the uplink waveform ischanged to DFT-S-OFDM (S2640).

Since the feasible P_max value of the DFT-S-OFDM is larger than that ofthe CP-OFDM, the uplink waveform of the PHR value transmitted by theterminal (explicit uplink waveform or reference uplink waveform) isDFT-S-OFDM. If the uplink waveform at the time of the actual uplinkallocation by the base station becomes the CP-OFDM, the P_max correctionvalue becomes negative (S2660) and the base station adds thecorresponding negative P_max correction value to the PH value receivedfrom the terminal, which is used for the uplink scheduling (determininguplink resource allocation and the number of allocated sub carriers)(S2670).

On the contrary, the uplink waveform (explicit uplink waveform orreference uplink waveform) of the PHR value transmitted by the terminalis the CP-OFDM, and if the uplink waveform at the time of the actualuplink allocation of the base station becomes the DFT-S-OFDM, the P_maxcorrection value becomes positive (S2650), and the base station adds thecorresponding positive P_max correction value to the PH value receivedfrom the terminal, which is used for the uplink scheduling (determininguplink resource allocation and the number of allocated sub carriers)(S2670).

The base station and the terminal performs the uplink transmission basedon the PHY layer indication method (PDCCH/DCI, or PUCCH/UCI) for thecontrol signaling operation for the uplink waveform indication, theindication method by a MAC CE in the MAC layer, the indication method byan RRC message (including configuration/information reconfigurationprocedure) in an RRC layer, and the indication method by the systeminformation.

Also, the base station includes a transmission of a waveform Indicationto be used for an actual UL transmission in an UL grant in an operationof performing uplink resource allocation determination and scheduling(S2680).

This uplink waveform indication indicator indicates whether thecorresponding uplink waveform is an initial uplink waveform indicationfor initial access (RACH MSG3) or a reference uplink waveform indicationfor a (default) uplink waveform indication which is a basic reference inthe connected state or whether the corresponding uplink waveformindication is an immediate uplink waveform indication to be applied toan actual uplink transmission later.

The method defining uplink waveform indication according to the layer ofthe control signal for transmitting the uplink waveform indicationincludes, for example, the example in which the uplink waveformindication information transmitted by the system information is theinitial uplink waveform indication, the information transmitted by theRRC signaling is the reference uplink waveform indication, theinformation transmitted by the PHR MAC CE or the UL Grant is theimmediate uplink waveform indication is provided, and all the cases inwhich the control transmission protocol layer and the control signalingare mapped by the initial/reference/immediate uplink waveform indicationare extendable provided.

The following Table 5 is an example in which the control transmissionprotocol layer and the control signaling are mapped to theinitial/reference/immediate uplink waveform indication.

TABLE 5 Mapping information Control transmission protocol layer andcontrol signaling uplink waveform indication type System InformationInitial uplink waveform indication RRC signalling Reference uplinkwaveform indication MAC CE (i.e., PHR) Reference or Immediate uplinkwaveform indication UL grant Immediate uplink waveform indication

There is ambiguity if the relationship that the control transmissionprotocol layer and the control signaling are mapped to theinitial/reference/immediate uplink waveform indication is not aone-to-one mapping. In Table 5, the MAC CE (i.e., PHR) shows an exampleof indicating both a reference and an immediate uplink waveformindication.

In this case, in addition to the uplink waveform indication, theinformation about the type of the uplink waveform indication, that is,the initial/reference/immediate uplink waveform indication may beprovided to eliminate the ambiguity of determination between theterminal and the base station.

In one embodiment of this operation, in addition to the uplink waveformindication, a type of an uplink waveform indication is defined as, forexample, 2 bits, and the following operation is performed. Theindication of the type of the uplink waveform indication includeslogically extendable cases.

The following table 6 shows the type information bits for the uplinkwaveform indication.

TABLE 6 Type information bits Uplink waveform indication informaiton bit2 bit uplink waveform indication type 00 Initial uplink waveformindication 01 Reference uplink waveform indication 10 Immediate uplinkwaveform indication 11 Reserved

FIG. 27 illustrates a structure of the terminal according to anembodiment of the present disclosure.

Referring to FIG. 27, a terminal 2700 may include a transceiver 2710, acontroller 2720, and a memory 2730. In the present disclosure, thecontroller 2720 may be defined as a circuit, an application specificintegrated circuit, or at least one processor.

The transceiver 2720 may transmit and receive signals to and from othernetwork entities. The transceiver 2710 may report, for example, the beammeasurement information to the base station, and receive the beam changecommand message. Further, for example, the transceiver 2710 may reportthe PHR and receive the information on the uplink waveform from the basestation.

The controller 2720 may control the overall operation of the terminalaccording to the embodiment of the present disclosure. For example, thecontroller 2720 may control a signal flow between each block to performthe operation according to the above-described flow chart.

The memory 2730 may store at least one of the informationtransmitted/received through the transceiver 2710 and the informationgenerated through the controller 2720.

FIG. 28 illustrates a configuration of a base station according to anembodiment of the present embodiment.

Referring to FIG. 28, the base station 2800 may include a transceiver2810, a controller 2820, and a memory 2830. In the present disclosure,the controller 2820 may be defined as a circuit, an application specificintegrated circuit, or at least one processor.

The transceiver 2810 may transmit and receive a signal to and fromanother network entity. The transceiver 2810 may receive, for example,the beam measurement information from the base station, and transmit thebeam change command message. Further, for example, the transceiver 2810may receive the PHR and transmit the information on the uplink waveformto the terminal.

The controller 2820 may control the overall operation of the terminalaccording to the embodiment of the present disclosure. For example, thecontroller 2820 may control a signal flow between each block to performthe operation according to the above-described flow chart.

The memory 2830 may store at least one of the informationtransmitted/received through the transceiver 2810 and the informationgenerated through the controller 2820.

Meanwhile, in the drawings illustrating a method in embodiments, theorder of description does not necessarily correspond to the order ofexecution, and the order relationship may be changed or executed inparallel.

Alternatively, the drawings illustrating the method of the presentdisclosure may omit some of the elements and may include only some ofthe elements without impairing the essence of the present disclosure.

Further, the method of the present disclosure may be carried out incombination with some or all of the contents included in each embodimentwithout departing from the essence of the present disclosure

Meanwhile, the exemplary embodiments of the present disclosure disclosedin the present specification and the accompanying drawings have beenprovided only as specific examples in order to help understand thepresent disclosure and do not limit the scope of the present disclosure.That is, it is obvious to those skilled in the art to which the presentdisclosure pertains that other change examples based on the technicalidea of the present disclosure may be made without departing from thescope of the present disclosure. Further, each embodiment may becombined and operated as needed.

Although the present disclosure has been described with variousembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A method of a terminal in a wireless communication system, the method comprising: receiving, from a base station, system information including first uplink waveform information for msg3 transmission; transmitting, to the base station, an msg3 based on the first uplink waveform information; receiving, from the base station, a radio resource control (RRC) message; transmitting, to the base station, data based on second uplink waveform information in case that the RRC message includes the second uplink waveform information; and transmitting, to the base station, the data based on the first uplink waveform information in case that the RRC message does not include the second uplink waveform information.
 2. The method of claim 1, wherein each of the first uplink waveform information and the second uplink waveform information indicates whether to enable discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM).
 3. The method of claim 1, wherein the system information including the first uplink waveform information is remaining minimum system information (RMSI).
 4. The method of claim 1, wherein the data is transmitted using at least one of cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) or discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based on the first uplink waveform information or the second uplink waveform information.
 5. A method of a base station in a wireless communication system, the method comprising: transmitting, to a terminal, system information including first uplink waveform information for msg3 transmission; receiving, from the terminal, an msg3 based on the first uplink waveform information; transmitting, to the terminal, a radio resource control (RRC) message; receiving, from the terminal, data based on second uplink waveform information in case that the RRC message includes the second uplink waveform information; and receiving, from the terminal, data based on the first uplink waveform information in case that the RRC message does not include the second uplink waveform information.
 6. The method of claim 5, wherein each of the first uplink waveform information and the second uplink waveform information indicates whether to enable discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM).
 7. The method of claim 5, wherein the system information including the first uplink waveform information is remaining minimum system information (RMSI).
 8. The method of claim 5, wherein the data is transmitted using at least one of cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) or discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based on the first uplink waveform information or the second uplink waveform information.
 9. A terminal in a wireless communication system, the terminal comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a base station, system information including first uplink waveform information for msg3 transmission, transmit, to the base station, an msg3 based on the first uplink waveform information, receive, from the base station, a radio resource control (RRC) message, transmit, to the base station, data based on second uplink waveform information in case that the RRC message includes the second uplink waveform information, and transmit, to the base station, the data based on the first uplink waveform information in case that the RRC setup message does not include the second uplink waveform information.
 10. The terminal of claim 9, wherein each of the first uplink waveform information and the second uplink waveform information indicates whether to enable discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM).
 11. The terminal of claim 9, wherein the system information including the first uplink waveform information is remaining minimum system information (RMSI).
 12. The terminal of claim 9, wherein the data is transmitted using at least one of cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) or discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based on the first uplink waveform information or the second uplink waveform information.
 13. A base station in a wireless communication system, the base station comprising: a transceiver; and a controller coupled with the transceiver and configured to: transmit, to a terminal, system information including first uplink waveform information for msg3 transmission, receive, from the terminal, an msg3 based on the first uplink waveform information, transmit, to the terminal, a radio resource control (RRC) message, receive, from the terminal, data based on second uplink waveform information in case that the RRC message includes the second uplink waveform information, and receive, from the terminal, data based on the first uplink waveform information in case that the RRC message does not include the second uplink waveform information.
 14. The base station of claim 13, wherein each of the first uplink waveform information and the second uplink waveform information indicates discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM).
 15. The base station of claim 13, wherein the system information including the first uplink waveform information is remaining minimum system information (RMSI).
 16. The base station of claim 13, wherein the data is transmitted using at least one of cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) or discrete fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based on the first uplink waveform information or the second uplink waveform information. 